FIS: disable Auth token auto fetch (#5656)

* FIS: disable Auth token auto fetch

* Punctuation

* Changelog

* Don't fail tests when no default app was created

* style

FirebaseInstallations/CHANGELOG.md

@@ -4,6 +4,7 @@
   NOTE: Installation Identifiers created by previous versions will be reset on Mac OS which can affect e.g. A/B Testing variants or debug device targeting for Firebase Messaging.
   iOS, TVOS and watchOS Installation Identifiers will not be affected. (#5603)
 - [changed] More readable server error console messages. (#5654)
+- [changed] Auth Token auto fetch disabled. (#5656)
 
 # v1.2.0 -- M69
 

FirebaseInstallations/Source/Library/FIRInstallations.m

@@ -89,10 +89,12 @@ NS_ASSUME_NONNULL_BEGIN
                                                       projectID:appOptions.projectID
                                                     GCMSenderID:appOptions.GCMSenderID
                                                     accessGroup:appOptions.appGroupID];
+
+  // `prefetchAuthToken` is disabled due to b/156746574.
   return [self initWithAppOptions:appOptions
                           appName:appName
         installationsIDController:IDController
-                prefetchAuthToken:YES];
+                prefetchAuthToken:NO];
 }
 
 /// The initializer is supposed to be used by tests to inject `installationsStore`.

FirebaseInstallations/Source/Tests/Integration/FIRInstallationsIntegrationTests.m

@@ -54,8 +54,7 @@ static BOOL sFIRInstallationsFirebaseDefaultAppConfigured = NO;
 
 - (void)tearDown {
   // Delete the installation.
-  [self.installations deleteWithCompletion:^(NSError *_Nullable error) {
-    XCTAssertNil(error);
+  [self.installations deleteWithCompletion:^(NSError *_Nullable error){
   }];
 
   // Wait for any pending background job to be completed.