BaseKeypointsDataset now inherits from HasPreprocessingParams

[BloodAxe]

Bugfixes

• BaseKeypointsDataset now inherits from HasPreprocessingParams to ensure preprocessing params for pose estimation model are saved properly.
• Changed default confidence threshold from 0.25 to 0.05 to match the default confidence threshold as is training recipe.

Improvement

SupportsReplaceNumClasses and HasPreprocessingParams are no Protocols anymore.
Motivation:

A Protocol class seems to do a lot of black vodoo magic:

class HasPreprocessingParams(Protocol):
   ...

class DetectionDataset(Dataset): # No HasPreprocessingParams
   ...

class COCODetectionDataset(DetectionDataset)

dataset = COCODetectionDataset(...)
isinstance(dataset, HasPreprocessingParams) # Returns True :exploding_head: 

Even not inheriting from HasPreprocessingParams but having the methods with matching signature implement, the isinstance returns True. Which may be really undesired/unexpected/coincidence.

[Louis-Dupont]

LGTM, just minor notes

[Louis-Dupont]

LGTM