BUG: .mode(dropna=False) doesn't work with nullable integers
Issue #58926
Edited `pandas.core.algorithms.mode` function so that mode(dropna=False) works with nullable integers.
PR of others before: https://github.com/pandas-dev/pandas/pull/58931

- [x] closes #58926 (Replace xxxx with the GitHub issue number)
- [ ] [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).
- [x] Added [type annotations](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#type-hints) to new arguments/methods/functions.
- [x] Added an entry in the latest `doc/source/whatsnew/vX.X.X.rst` file if fixing a bug or adding a new feature.

Thanks @halogen22 