test: migrate restore archived workflow run tests to testcontainers

[YB0y]

Summary

Migrate tests from api/tests/unit_tests/services/test_restore_archived_workflow_run.py
to testcontainers integration tests at
api/tests/test_containers_integration_tests/services/test_restore_archived_workflow_run.py.

Added two pure-logic tests (test_restore_initialization, test_convert_datetime_fields) to the existing TC file, which already covered test_restore_table_records_returns_rowcount and test_restore_table_records_unknown_table. Deleted the unit test file.

Part of #32454

Checklist

• This change requires a documentation update, included: Dify Document
• I understand that this PR may be closed in case there was no previous discussion or issues.
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.
• I ran make lint and make type-check (backend) and cd web && npx lint-staged (frontend) to appease the lint gods

[github-actions]

Pyrefly Diff

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[YB0y]

@asukaminato0721 Could you please review this?