Result File Dataclasses: IPA 7.X Updates

[mawelborn]

This PR adds support for new IPA 7.X models, including a new dataclass for summarization model predictions:

• Supports GenAI Classification models using the existing Classification dataclass.
  • Identifiable by classification.model.type == ModelGroupType.GENAI_CLASSIFICATION if needed.
• Supports GenAI Document Extraction models using the existing DocumentExtraction dataclass.
  • Identifiable by extraction.model.type == ModelGroupType.GENAI_EXTRACTION if needed.
• Supports GenAI Summarization models using the new Summarization dataclass.
  • Summarization is a subclass of Extraction with confidence and text attrs.
  • PredictionList has been updated with a new predictions.summarizations property.
• Supports partial failure of multifile submissions via new Document.failed, Document.error and Document.traceback attrs.
• Factored out repeated span and bounding box complexity using composition.
• Cleaned up some technical debt.