CLN: Removes module pandas.json
- [x] closes #19944
- [x] tests added / passed
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

I'm just not sure about which file should I add my changes in whatsnew, can anyone help me with that?
Hello @vitoriahmc! Thanks for submitting the PR.

 - There are no PEP8 issues in the file [`pandas/__init__.py`](https://github.com/vitoriahmc/pandas/blob/58a2f585631aa9afdd2cfa990c30577f4e48ea66/pandas/__init__.py) !

 - There are no PEP8 issues in the file [`pandas/tests/api/test_api.py`](https://github.com/vitoriahmc/pandas/blob/58a2f585631aa9afdd2cfa990c30577f4e48ea66/pandas/tests/api/test_api.py) !

 Thanks. We'll also want a release note in doc/source/whatsnew/v0.24.0.txt under the "removal of prior version" section. Looks good otherwise. > Thanks. We'll also want a release note in doc/source/whatsnew/v0.24.0.txt under the "removal of prior version" section. Looks good otherwise.

I've just updated it! thanks @vitoriahmc 

lib.py, parser.py, tslib.py are fair game as well