Add AppCheckDebugProvider

Author: andrewheard

FirebaseVertexAI/Tests/TestApp/VertexAITestApp/VertexAITestApp.swift

@@ -12,12 +12,14 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+import FirebaseAppCheck
 import FirebaseCore
 import SwiftUI
 
 @main
 struct VertexAITestApp: App {
   init() {
+    AppCheck.setAppCheckProviderFactory(AppCheckDebugProviderFactory())
     FirebaseApp.configure()
   }