🐛 Fix model kwargs handling in pipeline function

[tal7aouy]

Fixes how model-specific arguments are handled in the pipeline() function by replacing the problematic *model_kwargs positional argument with a proper model_kwargs keyword argument.

• Bug
• Feature

Changes

• Changed *model_kwargs to model_kwargs: Optional[Dict[str, Any]] = None
• Added initialization of empty dict when model_kwargs is None
• Properly forwarded model kwargs to loading functions

Why?

The previous implementation using *model_kwargs as positional arguments could silently drop model-specific arguments, leading to unexpected behavior. This change ensures model arguments are properly passed through and provides better type safety and API clarity.