Firestore: review app check credentials provider tests (#13914)

Author: MojtabaHs

Firestore/core/test/unit/credentials/firebase_app_check_credentials_provider_test.mm

@@ -181,7 +181,7 @@ - (nonnull NSString*)tokenDidChangeNotificationName {
 
 // Regression test for https://github.com/firebase/firebase-ios-sdk/issues/8895
 TEST(FirebaseAppCheckCredentialsProviderTest,
-     ListenForTokenChangesIgnoresUnrelatedNotifcations) {
+     ListenForTokenChangesIgnoresUnrelatedNotifications) {
   auto token_promise = std::make_shared<std::promise<std::string>>();
 
   FIRApp* app = testutil::AppForUnitTesting();