TST: add explicit csr explicit zero tests for GH28992
simple test case to check that explicitly setting a value to zero in a matrix with csr representation does not cause other values to change, specifically to be set to zero erroneously

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

@bakitybacon if you can fix up the linting issues & merge master, pls ping on green. can u merge master and ping on green Thanks @bakitybacon for the PR. closing as stale. 