Merge release 7.1.0 (#6944)

* Update versions for Release 7.1.0

* 7.1.0 update version of close source podspecs

* Release 7.1.0 cherry picks (#6917)

* FCM: Fix crash on iOS 14 when multiple app delegate completion methods are called (#6863)

* Fix crash on iOS 14 when multiple completion methods are called

* Fixed lint

* Addressed the PR comments & implemented unit tests

* Reverted auto-extracted method

* Re-organized tests

* Added completion handler for FIRAuth

* Manifest: GDT 8.0.1

* Update Changelogs for 7.1.0 (#6913)

* Changelogs

Co-authored-by: Mike Gerasimenko <github@gerasimenko.me>
Co-authored-by: Paul Beusterien <paulbeusterien@google.com>

* Bump GDT podspec version to 8.0.1

* 7.1.0 SPM Analytics (#6933)

* Carthage update 7.1.0 (#6943)

Co-authored-by: Mike Gerasimenko <github@gerasimenko.me>
Co-authored-by: Paul Beusterien <paulbeusterien@google.com>

FirebaseABTesting.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name             = 'FirebaseABTesting'
-  s.version          = '7.0.0'
+  s.version          = '7.1.0'
   s.summary          = 'Firebase ABTesting'
 
   s.description      = <<-DESC