Add ungrouped threat models to threat-model-grouping.model.yml

Author: owen-mc

shared/threat-models/ext/threat-model-grouping.model.yml

@@ -25,4 +25,6 @@ extensions:
       # Threat models that are not grouped with any other threat models.
       # (Note that all threat models are a child of "all" implicitly, and we
       # make it explicit here just to make sure all threat models are listed.)
+      - ["database-access-result", "all"]
+      - ["file-write", "all"]
       - ["reverse-dns", "all"]