Make DTI.get_loc/get_value require tzawareness-compat for datetimes
- [x] closes #30994 
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

> Can we first further discuss this at #30994 ?

Discuss away closing to clear the queue, will revisit