The admin bulk-delete path (prisma_client.delete_data) was never comparing
the DB return value against the requested tokens, so failed_tokens was
always empty for admins even when the DB silently skipped some tokens.
Adds the same mismatch check as the non-admin path, and a new test that
exercises admin bulk-delete returning fewer tokens than requested.
Fixes gap identified by Greptile review on #21609.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
