bugfix for FY5253 case with bunched yearends
Also achieves coverage for one of the uncovered branches in `FY5253.apply`

- [x] closes #14774
- [x] tests added / passed
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/18550?src=pr&el=h1) Report
> Merging [#18550](https://codecov.io/gh/pandas-dev/pandas/pull/18550?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/2a0e54bc841f27164b116135ebda4b74bae2fc4a?src=pr&el=desc) will **decrease** coverage by `0.03%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/18550/graphs/tree.svg?token=eZ4WkYLtcO&src=pr&height=150&width=650)](https://codecov.io/gh/pandas-dev/pandas/pull/18550?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #18550      +/-   ##
==========================================
- Coverage   91.35%   91.31%   -0.04%     
==========================================
  Files         164      164              
  Lines       49802    49804       +2     
==========================================
- Hits        45496    45478      -18     
- Misses       4306     4326      +20
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.11% <100%> (-0.03%)` | :arrow_down: |
| #single | `40.81% <0%> (-0.07%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/18550?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/tseries/offsets.py](https://codecov.io/gh/pandas-dev/pandas/pull/18550?src=pr&el=tree#diff-cGFuZGFzL3RzZXJpZXMvb2Zmc2V0cy5weQ==) | `96.98% <100%> (+0.08%)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/18550?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/plotting/\_converter.py](https://codecov.io/gh/pandas-dev/pandas/pull/18550?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19jb252ZXJ0ZXIucHk=) | `63.44% <0%> (-1.82%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/18550?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.81% <0%> (-0.1%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/18550?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/18550?src=pr&el=footer). Last update [2a0e54b...edb8b85](https://codecov.io/gh/pandas-dev/pandas/pull/18550?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/18550?src=pr&el=h1) Report
> Merging [#18550](https://codecov.io/gh/pandas-dev/pandas/pull/18550?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/13f6267207dd1f140b12d7718277508eff5c1efb?src=pr&el=desc) will **decrease** coverage by `0.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/18550/graphs/tree.svg?width=650&height=150&src=pr&token=eZ4WkYLtcO)](https://codecov.io/gh/pandas-dev/pandas/pull/18550?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #18550      +/-   ##
==========================================
- Coverage   91.59%   91.58%   -0.02%     
==========================================
  Files         153      153              
  Lines       51221    51223       +2     
==========================================
- Hits        46917    46911       -6     
- Misses       4304     4312       +8
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.44% <100%> (ø)` | :arrow_up: |
| #single | `40.67% <0%> (-0.11%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/18550?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/tseries/offsets.py](https://codecov.io/gh/pandas-dev/pandas/pull/18550/diff?src=pr&el=tree#diff-cGFuZGFzL3RzZXJpZXMvb2Zmc2V0cy5weQ==) | `96.94% <100%> (+0.08%)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/18550/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/18550/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.81% <0%> (-0.1%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/18550?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/18550?src=pr&el=footer). Last update [13f6267...566e498](https://codecov.io/gh/pandas-dev/pandas/pull/18550?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 cc @cancan101 if you could have a look / try out. release note pls. Ping. cc @ronif can you have a look. Just rebased and pushed; no new changes. thanks