[BUGFIX][IOS][LINKS] Update linking restorationHandler implementation for iOS12 (#2216)

* Update iOS linking restorationHandler implementation

Author: iljadaderko

ios/RNFirebase/links/RNFirebaseLinks.h

@@ -7,12 +7,23 @@
 #import <React/RCTBridgeModule.h>
 #import <React/RCTEventEmitter.h>
 
-@interface RNFirebaseLinks : RCTEventEmitter<RCTBridgeModule>
+@interface RNFirebaseLinks : RCTEventEmitter <RCTBridgeModule>
 
 + (_Nonnull instancetype)instance;
 
-- (BOOL)application:(UIApplication *)app openURL:(NSURL *)url options:(NSDictionary<UIApplicationOpenURLOptionsKey,id> *)options;
-- (BOOL)application:(UIApplication *)application continueUserActivity:(NSUserActivity *)userActivity restorationHandler:(void (^)(NSArray *))restorationHandler;
+- (BOOL)application:(UIApplication *)app
+            openURL:(NSURL *)url
+            options:(NSDictionary<UIApplicationOpenURLOptionsKey, id> *)options;
+
+- (BOOL)application:(UIApplication *)application
+    continueUserActivity:(NSUserActivity *)userActivity
+      restorationHandler:
+        #if defined(__IPHONE_12_0) && (__IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_12_0)
+          (nonnull void (^)(NSArray<id<UIUserActivityRestoring>> *_Nullable))restorationHandler;
+        #else
+          (nonnull void (^)(NSArray *_Nullable))restorationHandler;
+        #endif // __IPHONE_12_0
+
 - (void)sendLink:(NSString *)link;
 
 @end
@@ -23,4 +34,3 @@
 #endif
 
 #endif
-

ios/RNFirebase/links/RNFirebaseLinks.m

@@ -55,7 +55,12 @@ - (BOOL)application:(UIApplication *)app
 
 - (BOOL)application:(UIApplication *)application
 continueUserActivity:(NSUserActivity *)userActivity
- restorationHandler:(void (^)(NSArray *))restorationHandler {
+restorationHandler:
+    #if defined(__IPHONE_12_0) && (__IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_12_0)
+        (nonnull void (^)(NSArray<id<UIUserActivityRestoring>> *_Nullable))restorationHandler {
+    #else
+        (nonnull void (^)(NSArray *_Nullable))restorationHandler {
+    #endif  // __IPHONE_12_0
     if ([userActivity.activityType isEqualToString:NSUserActivityTypeBrowsingWeb]) {
         return [[FIRDynamicLinks dynamicLinks]
                 handleUniversalLink:userActivity.webpageURL