Add UIApplicationDelegate to silence AppDelegateSwizzler error

FirebaseVertexAI/Sample/VertexAISample/VertexAISampleApp.swift

@@ -16,9 +16,10 @@ import FirebaseAppCheck
 import FirebaseCore
 import SwiftUI
 
-@main
-struct VertexAISampleApp: App {
-  init() {
+class AppDelegate: NSObject, UIApplicationDelegate {
+  func application(_ application: UIApplication,
+                   didFinishLaunchingWithOptions launchOptions: [UIApplication
+                     .LaunchOptionsKey: Any]? = nil) -> Bool {
     // Recommendation: Protect your Vertex AI API resources from abuse by preventing unauthorized
     // clients using App Check; see https://firebase.google.com/docs/app-check#get_started.
     AppCheck.setAppCheckProviderFactory(AppCheckNotConfiguredFactory())
@@ -27,12 +28,20 @@ struct VertexAISampleApp: App {
 
     if let firebaseApp = FirebaseApp.app(), firebaseApp.options.projectID == "mockproject-1234" {
       guard let bundleID = Bundle.main.bundleIdentifier else { fatalError() }
-      fatalError("You must create and/or download a valid `GoogleService-Info.plist` file for"
-        + " \(bundleID) from https://console.firebase.google.com to run this sample. Replace the"
-        + " existing `GoogleService-Info.plist` file in the `FirebaseVertexAI/Sample` directory"
-        + " with this new file.")
+      fatalError("""
+      You must create and/or download a valid `GoogleService-Info.plist` file for \(bundleID) from \
+      https://console.firebase.google.com to run this sample. Replace the existing \
+      `GoogleService-Info.plist` file in the `FirebaseVertexAI/Sample` directory with this new file.
+      """)
     }
+
+    return true
   }
+}
+
+@main
+struct VertexAISampleApp: App {
+  @UIApplicationDelegateAdaptor var appDelegate: AppDelegate
 
   var body: some Scene {
     WindowGroup {