[Vertex AI] Update log message when API is not enabled

Author: andrewheard

FirebaseVertexAI/Sources/GenerativeAIService.swift

@@ -265,23 +265,33 @@ struct GenerativeAIService {
   private func logRPCError(_ error: RPCError) {
     // TODO(andrewheard): Remove this check after the Vertex AI in Firebase API launch.
     if error.isFirebaseMLServiceDisabledError() {
-      VertexLog.error(code: .vertexAIInFirebaseAPIDisabled, """
+      let message = """
       The Vertex AI for Firebase SDK requires the Firebase ML API `firebaseml.googleapis.com` to \
-      be enabled for your project. Get started in the Firebase Console \
-      (https://console.firebase.google.com/project/\(projectID)/genai/vertex) or verify that the \
-      API is enabled in the Google Cloud Console \
-      (https://console.developers.google.com/apis/api/firebaseml.googleapis.com/overview?project=\
-      \(projectID)).
-      """)
+      be enabled for your project. Enable it by visiting the the Firebase Console at
+      https://console.firebase.google.com/project/\(projectID)/genai/vertex then retry. If you
+      enabled this API recently, wait a few minutes for the action to propagate to our systems and
+      retry.
+      """
+      #if DEBUG
+        fatalError(message)
+      #else
+        VertexLog.error(code: .vertexAIInFirebaseAPIDisabled, message)
+      #endif // DEBUG
     }
 
     if error.isVertexAIInFirebaseServiceDisabledError() {
-      VertexLog.error(code: .vertexAIInFirebaseAPIDisabled, """
+      let message = """
       The Vertex AI for Firebase SDK requires the Firebase Vertex AI API \
-      `firebasevertexai.googleapis.com` to be enabled for your project. Get started by visiting \
-      the Firebase Console at: \
-      https://console.firebase.google.com/project/\(projectID)/genai/vertex
-      """)
+      `firebasevertexai.googleapis.com` to be enabled for your project. Enable it by visiting the \
+      the Firebase Console at https://console.firebase.google.com/project/\(projectID)/genai/vertex
+      then retry. If you enabled this API recently, wait a few minutes for the action to propagate
+      to our systems and retry.
+      """
+      #if DEBUG
+        fatalError(message)
+      #else
+        VertexLog.error(code: .vertexAIInFirebaseAPIDisabled, message)
+      #endif // DEBUG
     }
   }