ENH: EA._cast_pointwise_result
- [x] closes #59895 (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).
- [ ] 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.

Still have a bunch of pyarrow tests involving duration/timestamp dtypes failing.  Also need to update/remove the test files' _cast_pointwise_result methods.

xref #56430, could close that with a little effort.

I suspect a bunch of "pyarrow dtype retention" tests are solved by this, will update as I check.
The pyarrow duration stuff is caused by an upstream issue https://github.com/apache/arrow/issues/40620 @rhshadrach i think you had a recent issue/pr involving retaining nullable dtypes in a .map?