BUG: Respect check_dtype in assert_series_equal
- [x] closes #32747
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`

I'm not sure if https://github.com/pandas-dev/pandas/blob/master/pandas/_testing.py#L1174 needs to change too?

cc @jorisvandenbossche 