REGR: Series access with Index of tuples/frozenset
- [x] closes #35534 
- [x] closes #35747
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

Thanks @jreback, I reworked the logic. This patch now retains much more of the original behavior. 

When one tries to find a tuple key in a Series with an Index, originally you got the message `Can only tuple-index with a MultiIndex`. As this is no longer true, I've changed this to `key of type tuple not found and not a MultiIndex`. @simonjayhawkins this is ok to merge on green if you haven't tagged (otherwise can move to 1.1.3) > @simonjayhawkins this is ok to merge on green if you haven't tagged (otherwise can move to 1.1.3)

yep restarting ci. known failure

```
=========================== short test summary info ===========================
FAILED pandas/tests/plotting/test_groupby.py::TestDataFrameGroupByPlots::test_series_groupby_plotting_nominally_works
= 1 failed, 74726 passed, 1786 skipped, 1130 xfailed, 6 xpassed, 67 warnings in 1183.92s (0:19:43) =
``` ok let's defer this one LGTM whatsnew-placement notwithstanding Failure is different this time.

```
=========================== short test summary info ===========================
FAILED pandas/tests/io/test_parquet.py::TestParquetPyArrow::test_s3_roundtrip_for_dir[partition_col0]
= 1 failed, 74674 passed, 1905 skipped, 1108 xfailed, 6 xpassed, 284 warnings in 1178.42s (0:19:38) =
```
 > Failure is different this time.

I think this one is affecting all PRs @jreback Same unrelated parquet failure; the groupby plots failure no longer occurs. Thanks for the review @jbrockmendel, changes made and checks pass. thanks @rhshadrach for the followon's can open an issue if you want so we can track. @meeseeksdev backport 1.1.x