[ENH] Make OpenMLSetup inherit OpenMLBase

[moksha-hub]

Summary

Makes OpenMLSetup inherit from OpenMLBase to enable tagging and shared API functionality as requested in #1647.

Changes

• Removed @dataclass decorator; replaced with explicit __init__ with same validation
• Added id property (returns setup_id)
• Added _entity_letter() classmethod returning 's'
• Implemented _get_repr_body_fields() using the _apply_repr_template from OpenMLBase
• Kept existing _to_dict() implementation
• Added _parse_publish_response() that raises NotImplementedError
• Overrode publish() to raise TypeError (setups cannot be uploaded by clients)
• Converted OpenMLParameter from @dataclass to regular class for consistency
  Closes [ENH] make OpenMLSetup inherit OpenMLBase #1647

[moksha-hub]

@geetu040 please have a review.
Thank you.

[moksha-hub]

@geetu040 have a look if any changes are necessary i will make.