feat(documents): validate extractions from IXP models deployed to a folder

[PG-Thomas]

Stacks on #1933 (folder extraction), which stacks on #1929.

What

Models deployed to a folder can't use the project and tag validation route (.../validation/start). Their validation is a separate artifacts flow, and the caller opens the Action Center task. This PR adds:

• start_model_extraction_validation(extraction_response, storage_bucket_name, storage_bucket_folder_path, storage_bucket_directory_path=None, folder_key=None):
  • It reads the model's taxonomy from models/{name}.
  • It starts extraction-validation/artifacts/start, then waits for content-validation-data.
  • It returns the operation_id and the content_validation_data.
• create_model_validation_task(title, content_validation_data, priority=None, folder_key | folder_path): it opens a DocumentValidationTask through GenericTasks/CreateTask and returns the Task, so an agent can suspend on WaitTask.
• retrieve_model_extraction_validation_result(operation_id): it reads extraction-validation/artifacts/validation-result/{id}. Until the reviewer submits, DU returns {"Result": {}}, and the method then raises OperationNotCompleteException.

The taxonomy and the content validation data are passed through unchanged (PascalCase), because the artifacts and task endpoints receive them back as-is.

Task is imported inside the two task methods. A module-level import creates an import cycle (action_center → common.interrupt_models → documents).

How it was tested

• Unit tests (sync and async):
  • The artifacts request body, including that it has no folder header.
  • Polling for content-validation-data.
  • The task body and its folder header.
  • The validated result, both submitted and not yet submitted.
• The uipath-platform suite, ruff and mypy all pass.
• Live run against a production tenant with folder-deployed models:
  • The extraction worked. Validation data was written to the solution's bucket, both with and without a directory path.
  • A DocumentValidationTask was created with priority Low. Read back, it showed the right type, priority and data. It was then deleted.
  • Before submit, the result raised OperationNotCompleteException ... Current status: Pending.
  • I did not exercise the submitted path in this live run. The same route is in production use in the invoice-processing solution.

Version bumped to 0.2.37.