Remove unused configuration keys

[aduth]

🛠 Summary of changes

Removes unused configuration keys in application.yml.default / IdentityConfig:

• acuant_assure_id_password: Last reference removed in LG-11892: Remove Assure ID integration from the backend #10198
• acuant_assure_id_subscription_id: Last reference removed in LG-11892: Remove Assure ID integration from the backend #10198
• acuant_assure_id_url: Last reference removed in LG-11892: Remove Assure ID integration from the backend #10198
• acuant_assure_id_username: Last reference removed in LG-11892: Remove Assure ID integration from the backend #10198
• acuant_create_document_timeout: Last reference removed in LG-11892: Remove Assure ID integration from the backend #10198
• acuant_facial_match_url: Last reference removed in LG-11892: Remove Assure ID integration from the backend #10198
• acuant_get_results_timeout: Last reference removed in LG-11892: Remove Assure ID integration from the backend #10198
• acuant_passlive_url: Last reference removed in LG-11892: Remove Assure ID integration from the backend #10198
• acuant_timeout: Last reference removed in LG-11892: Remove Assure ID integration from the backend #10198
• acuant_upload_image_timeout: Last reference removed in LG-11892: Remove Assure ID integration from the backend #10198
• doc_auth_custom_ui_enabled: Added in LG-11845: feature flag doc_auth_custom_ui_enabled. #9822, never used
• doc_auth_s3_request_timeout: Last reference removed in LG-9611 Remove async document capture code #8377
• doc_auth_sdk_capture_orientation: Added in LG-11569: Add feature flag for reorienting SDK capture #9624, never used
• vendor_status_acuant: Last reference removed in LG-11892: Remove Assure ID integration from the backend #10198

I was hoping to introduce some automated testing to identify these keys in continuous integration (see 276fbbc), but it didn't work as expected. I'm not sure it could work, since specs are parallelized across many runners, so each individual runner doesn't have access to a global shared pool of tracked calls to config methods.

Instead, I put together a bash script to identify unused keys:

rails runner ['File.write("keys.txt", IdentityConfig.store.to_h.keys.join("\n"))']

while read key; do
  hits=$(ag "$key" . --nofilename --nobreak --ignore-dir={node_modules,tmp,public} --ignore={keys.txt,config/application.yml.default,lib/identity_config.rb} | wc -l)
  if [ "$hits" -eq "0" ]; then
    echo "$key"
  fi
done < keys.txt

📜 Testing Plan

Verify there are no references to the removed configuration keys.