Remove annotations to make CI happy
I must have been a little quick in merging #26802 as it looks like this is causing mypy failures in CI.

Most of these are pretty niche and I think a result of import machinery. Will try to dive deeper later but this should get things green for now
Annotations might just not be possible here given the dynamic nature. Here's a relevant mypy discussion:

https://github.com/python/mypy/issues/5059 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26820?src=pr&el=h1) Report
> Merging [#26820](https://codecov.io/gh/pandas-dev/pandas/pull/26820?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/634577eb9ae53da6c16a54773f9f9f8016e2a1ed?src=pr&el=desc) will **decrease** coverage by `<.01%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/26820/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/26820?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #26820      +/-   ##
==========================================
- Coverage   91.86%   91.86%   -0.01%     
==========================================
  Files         179      179              
  Lines       50707    50707              
==========================================
- Hits        46583    46580       -3     
- Misses       4124     4127       +3
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.45% <ø> (ø)` | :arrow_up: |
| #single | `41.09% <ø> (-0.1%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/26820?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/gcs.py](https://codecov.io/gh/pandas-dev/pandas/pull/26820/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2djcy5weQ==) | `100% <ø> (ø)` | :arrow_up: |
| [pandas/io/s3.py](https://codecov.io/gh/pandas-dev/pandas/pull/26820/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL3MzLnB5) | `100% <ø> (ø)` | :arrow_up: |
| [pandas/compat/\_optional.py](https://codecov.io/gh/pandas-dev/pandas/pull/26820/diff?src=pr&el=tree#diff-cGFuZGFzL2NvbXBhdC9fb3B0aW9uYWwucHk=) | `100% <ø> (ø)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/26820/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `88.88% <0%> (-11.12%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/26820/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `96.88% <0%> (-0.12%)` | :arrow_down: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/26820/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `90.94% <0%> (+0.1%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26820?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26820?src=pr&el=footer). Last update [634577e...f463aeb](https://codecov.io/gh/pandas-dev/pandas/pull/26820?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26820?src=pr&el=h1) Report
> Merging [#26820](https://codecov.io/gh/pandas-dev/pandas/pull/26820?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/634577eb9ae53da6c16a54773f9f9f8016e2a1ed?src=pr&el=desc) will **decrease** coverage by `<.01%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/26820/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/26820?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #26820      +/-   ##
==========================================
- Coverage   91.86%   91.86%   -0.01%     
==========================================
  Files         179      179              
  Lines       50707    50706       -1     
==========================================
- Hits        46583    46579       -4     
- Misses       4124     4127       +3
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.45% <ø> (-0.01%)` | :arrow_down: |
| #single | `41.12% <ø> (-0.07%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/26820?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/gcs.py](https://codecov.io/gh/pandas-dev/pandas/pull/26820/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2djcy5weQ==) | `100% <ø> (ø)` | :arrow_up: |
| [pandas/io/s3.py](https://codecov.io/gh/pandas-dev/pandas/pull/26820/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL3MzLnB5) | `100% <ø> (ø)` | :arrow_up: |
| [pandas/compat/\_optional.py](https://codecov.io/gh/pandas-dev/pandas/pull/26820/diff?src=pr&el=tree#diff-cGFuZGFzL2NvbXBhdC9fb3B0aW9uYWwucHk=) | `100% <ø> (ø)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/26820/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `88.88% <0%> (-11.12%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/26820/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `96.88% <0%> (-0.12%)` | :arrow_down: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/26820/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `90.94% <0%> (+0.1%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26820?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26820?src=pr&el=footer). Last update [634577e...665f92f](https://codecov.io/gh/pandas-dev/pandas/pull/26820?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 lgtm. merge on green.