Added test for sort_index parameter multiindex 'sort_remaining' = False
- [x] closes #24247
- [x] [Tests added and passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#writing-tests)

Issue fixed on main, added validation tests
Please ensure you run precommit to fix code check issues: https://pandas.pydata.org/docs/development/contributing_codebase.html#contributing-pre-commit Hi @mroeschke :)
All the checks have passed. Hi @phofl 
I fixed the code according to your notes, is is ok now? You didn't address any of my comments > You didn't address any of my comments

Sorry, I forgot to commit :)
Now you should see it. thx @NoyHanan 