[Tiny models] Auto-push updated_tiny_model_summary.json to Hub summary repo after upload
When upload=True and hub_summary_repo is set, push the merged
updated_tiny_model_summary.json back to hub_summary_repo as
tiny_model_summary.json so the next CI run has an up-to-date
models_to_skip list. Failures are caught and logged without
aborting the run.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>