Replaces the create_lower_mouth_mask function in
modules/processors/frame/face_swapper.py with a version that has
corrected indentation. This resolves an "IndentationError: unexpected indent"
that was preventing the application from starting.
The replaced block also includes minor robustness improvements for
ROI calculations and Gaussian blur kernel sizes within this function
and implicitly updated other related utility functions that were part of the
provided code block.
44ef1fdcac