CLN: dont special-case DatetimeArray indexing
- [x] closes #36210
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

cc @jorisvandenbossche 
can you add some tests that lock this down (eg from the OP).

I think this would be ok to push for 1.2 with a whatsnew note.

cc @jorisvandenbossche  whatsnew+test+green any other thoughts here?  after this i can get back to de-duplicating EA code Test amended + green Thanks Brock!