BUG: isin check incorrect with uint64 dtype
- [ ] closes #59609 
- [ ] [Tests added and passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#writing-tests) if fixing a bug or adding a new feature
- [ ] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).
- [ ] Added [type annotations](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#type-hints) to new arguments/methods/functions.
- [ ] Added an entry in the latest `doc/source/whatsnew/vX.X.X.rst` file if fixing a bug or adding a new feature.

These test failures come from changing the ```np_find_common_type``` method, which the ```isin``` method uses to cast the values to a common type. The problem is that when taking a int64 and uint64, the common type is float64, causing precision errors. I instead had ```np_find_common_type``` return an object type, which fixed the issue for the bug but obviously caused a lot of test issues.

Should I only edit inside the ```isin``` method, or should I change the ```np_find_common_type```? Any advice would be helpful. This pull request is stale because it has been open for thirty days with no activity. Please [update](https://pandas.pydata.org/pandas-docs/stable/development/contributing.html#updating-your-pull-request) and respond to this comment if you're still interested in working on this. Thanks for the pull request, but it appears to have gone stale. If interested in continuing, please merge in the main branch, address any review comments and/or failing tests, and we can reopen.