BUG: failure to cast all-int floating dtypes when setting into int dtypes
- [ ] closes #xxxx
- [x] tests added / passed
- [x] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit) for how to run them
- [x] whatsnew entry

Overlap with (but not rebased on top of) #44275
user facing at all? > user facing at all?

yes, just updated with whatsnew small comment, otherwise lgtm Thx @jbrockmendel 