[Infra] Fix Swift 6 warning in FirebaseAppTests.swift (#13627)

Author: ncooke3

FirebaseCore/Tests/SwiftUnit/FirebaseAppTests.swift

@@ -340,22 +340,20 @@ class FirebaseAppTests: XCTestCase {
   // MARK: - Helpers
 
   private func expectAppConfigurationNotification(appName: String, isDefaultApp: Bool) {
-    let expectedUserInfo: NSDictionary = [
+    let expectedUserInfo: [String: Any] = [
       "FIRAppNameKey": appName,
       "FIRAppIsDefaultAppKey": NSNumber(value: isDefaultApp),
       "FIRGoogleAppIDKey": Constants.Options.googleAppID,
     ]
 
     expectation(forNotification: NSNotification.Name.firAppReadyToConfigureSDK,
                 object: FirebaseApp.self, handler: { notification -> Bool in
-                  if let userInfo = notification.userInfo {
-                    if expectedUserInfo.isEqual(to: userInfo) {
-                      return true
-                    }
-                  } else {
+                  guard let userInfo = notification.userInfo else {
                     XCTFail("Failed to unwrap notification user info")
+                    return false
                   }
-                  return false
+                  return NSDictionary(dictionary: expectedUserInfo) ==
+                    NSDictionary(dictionary: userInfo)
                 })
   }
 }