Moving `__call__` logic into Python's C-API means error messages
caused by operators reference the code of the caller instead of the
call from `.scripts/modules/bpy/ops.py`.
When a full call stack is available this isn't so important,
however when logging callers it's not useful to log the call
from `ops.py`.
There minor performance advantages for moving from Python to C++
however this wasn't a significant consideration for the change.
Note that this is a fairly direct conversion from Python to C++,
there is room for refactoring to simplify the calling logic.
See #144746 for the motivation & #147448 for further improvements.
Ref !145344
877283a09a