use correct variable (#12971)

scripts/make_release_notes.py

@@ -42,7 +42,7 @@ PRODUCTS = {
     'FirebaseFunctions/CHANGELOG.md': '{{cloud_functions}}',
     'FirebaseRemoteConfig/CHANGELOG.md': '{{remote_config}}',
     'FirebasePerformance/CHANGELOG.md': '{{perfmon}}',
-    'FirebaseVertexAI/CHANGELOG.md': '{{vertexai}}',
+    'FirebaseVertexAI/CHANGELOG.md': '{{firebase_vertexai}}',
 }