CLN: _wrap_applied_output
- [ ] closes #xxxx
- [ ] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

All if statements above the changed block return, so we can remove the else's and flatten out the structure a bit.
Failure is unrelated. thanks @rhshadrach 

wouldn't be averse to simplifying this function *even* more with have some helper functions (and would location them in *another* module if possible as free functions and just passing in what you need), rather than locating them on the groupby objects themselves (e.g. to make this even easier to follow the cases)