chore: exclude generated files from GCA review (#14503)

These files are derived from IDL artifacts or wholly templated.

Main change from previous attempt: string encapsulating the patterns,
based on prior art in some other repos

Author: shollyman

.gemini/config.yaml

@@ -11,3 +11,6 @@ code_review:
     summary: false
     code_review: true
     include_drafts: true
+ignore_patterns:
+  - "*.pb.go"
+  - "**/internal/version.go"