OPS: Remove mask_cmp_op fallback behavior
- [x] closes #28079 
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

xref #28050. 

To make the Series vs DataFrame behavior consistent, the two main options are a) change the DataFrame behavior (this PR) or b) change the Series behavior.  The latter is complicated by the fact that for object dtypes the Series comparisons go through comp_method_OBJECT_ARRAY instead of the numpy op, so we would still have to change the complex-case test changed here.