Use application:openURL to handle ios cold start

Following https://firebase.google.com/docs/dynamic-links/ios/receive#objective-c_3 (step 7)

Author: albertopq

src/ios/AppDelegate+FirebaseDynamicLinksPlugin.m

@@ -14,6 +14,29 @@ + (void)load {
     });
 }
 
+- (BOOL)application:(UIApplication *)app
+            openURL:(NSURL *)url
+            options:(NSDictionary<NSString *, id> *)options {
+  return [self application:app
+                   openURL:url
+         sourceApplication:options[UIApplicationOpenURLOptionsSourceApplicationKey]
+                annotation:options[UIApplicationOpenURLOptionsAnnotationKey]];
+}
+
+- (BOOL)application:(UIApplication *)application
+            openURL:(NSURL *)url
+  sourceApplication:(NSString *)sourceApplication
+         annotation:(id)annotation {
+  FIRDynamicLink *dynamicLink = [[FIRDynamicLinks dynamicLinks] dynamicLinkFromCustomSchemeURL:url];
+
+  if (dynamicLink) {
+      FirebaseDynamicLinksPlugin* dl = [self.viewController getCommandInstance:@"FirebaseDynamicLinks"];
+      [dl postDynamicLink:dynamicLink];
+    return YES;
+  }
+  return NO;
+}
+
 + (void)swizzleMethod:(SEL)originalSelector {
     Class class = [self class];
     NSString *selectorString = NSStringFromSelector(originalSelector);