CLN: Fix mypy error in 'pandas/tests/computation/test_eval.py'
Added explicit typing annotation for _parsers: Dict[str, Type[BaseExprVisitor]]
Also added some import for Dict, Type and BaseExprVisitor

- [x] relates to #28926 
- [x] tests added / passed
- [x] passes `black pandas`
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry
