stereo vision pipeline: multi experience feature match visualization function call should not be put in ransac_module

[cheneyuwu]

I've always assumed that the MEL feature matching visualization happens in the mel_matcher_module with an enabling flag: https://github.com/utiasASRL/vtr3/blob/3eb447d12d9349964358c4a7a62033af82311570/main/src/vtr_vision/src/modules/matching/mel_matcher_module.cpp#L54

However, the visualization function is actually called in ransac_module here: https://github.com/utiasASRL/vtr3/blob/aae397c80642b8bc3e6089342ede4e085db9dba3/main/src/vtr_vision/src/modules/ransac/ransac_module.cpp#L202

Does not seem to be a good idea to put a use-case-specific visualization function in RansacModule, which is supposed to be a more generic module.