iOS Baseline to build upon for the Admob 2021 SDK (#625)

* removed nativeAdExpress and rewardedVideo iOS impls
* removed extra comma in admob testapp project

Author: DellaBitta

admob/src/android/admob_android.h

@@ -66,7 +66,7 @@ METHOD_LOOKUP_DECLARATION(request_config_builder,
                           REQUESTCONFIGURATIONBUILDER_METHODS);
 
 // Change codes used when receiving state change callbacks from the Java
-// BannerViewHelper and NativeExpressAdViewHelper objects.
+// BannerViewHelperHelper object.
 enum AdViewChangeCode {
   // The callback indicates the presentation state has changed.
   kChangePresentationState = 0,

admob/src/common/interstitial_ad.cc

@@ -20,9 +20,6 @@
 #include "admob/src/common/interstitial_ad_internal.h"
 #include "app/src/assert.h"
 #include "app/src/include/firebase/future.h"
-#include "app_framework.h"
-
-using app_framework::LogDebug;
 
 namespace firebase {
 namespace admob {