ci: add gemini code assist config (#62560)

Configures gemini to not interact with new pull requests, only review on
demand

PR Close #62560

.gemini/config.yaml

@@ -0,0 +1,10 @@
+have_fun: false
+code_review:
+  disable: false
+  comment_severity_threshold: MEDIUM
+  max_review_comments: -1
+  pull_request_opened:
+    help: false
+    summary: false
+    code_review: false
+ignore_patterns: []

.pullapprove.yml

@@ -318,6 +318,7 @@ groups:
           '.devcontainer/**/{*,.*}',
           '.github/**/{*,.*}',
           '.husky/**/{*,.*}',
+          '.gemini/**/{*,.*}',
           '.ng-dev/**/{*,.*}',
           '.vscode/**/{*,.*}',
           '.yarn/**/{*,.*}',