BUG: StataWriter value_label encoding
- [x] closes #46750
- [x] [Tests added and passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#writing-tests) 
- [x] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).
- [x] Added an entry in  `doc/source/whatsnew/v1.5.0.rst`

thanks @eirki 