TST: update pre-commit config to only exclude extension from bare pytest.raises check
With #38920 I eliminated all instances of `pytest.raise` without `match=msg` in pandas/tests/computation and pandas/tests/io. #38799 was happening around the same time and missed that they were fixed. So this closes the loop and now only pandas/tests/extension needs to be excluded from the linting check.

I don't think the bare `pytest.raise`s in pandas/tests/extensions will be removed. They are in a pretty complex inheritance hierarchy and reused for many different types of errors and error messages. So I propose that this PR closes #30999.

- [x] closes #30999 
- [ ] tests added / passed
- [x] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing.html#code-standards) for how to run them
- [ ] whatsnew entry
