When enable_metadata_archive_db=True, the previous filter logic would
repeatedly try to fetch metadata for models that were already confirmed
to not exist on CivitAI (from_civitai=False, civitai_deleted=True).
The fix adds a skip condition to exclude models that:
1. Are confirmed not from CivitAI (from_civitai=False)
2. Are marked as deleted/not found on CivitAI (civitai_deleted=True)
3. Either have no archive DB enabled, or have already been checked (db_checked=True)
This prevents unnecessary API calls to CivArchive for user-trained models
or models from non-CivitAI sources.
Fixes repeated "Error fetching version of CivArchive model by hash" logs
for models that will never be found on CivitAI/CivArchive.