[SDK-179] iOS 12: Chained rich interstitial messages do not work (#410)

Fix Rich Interstitial chaining

Author: nzagorchev

Leanplum-SDK/Classes/MessageTemplates/ViewControllers/LPMessageTemplateUtilities.m

@@ -19,7 +19,7 @@ +(void)presentOverVisible:(UIViewController *) viewController
         UIViewController *topViewController = [self visibleViewController];
         // if topViewController is getting dismissed, get view controller that presented it and let it present our new view controller,
         // otherwise we can assume that our topViewController will be in view hierarchy when presenting new view controller
-        if (topViewController.beingDismissed) {
+        if (topViewController.isBeingDismissed) {
             [[topViewController presentingViewController] presentViewController:viewController animated:YES completion:nil];
         } else {
             [topViewController presentViewController:viewController animated:YES completion:nil];
@@ -31,9 +31,14 @@ +(void)dismissExisitingViewController:(nullable void (^)(void)) completion
 {
     UIViewController *topViewController = [self visibleViewController];
 
-    // dismiss html view controller for now
+    // Dismiss the view controller if another message will be presented (without user interaction)
+    // Dismiss only html view controller for now
     if ([topViewController isKindOfClass:[LPWebInterstitialViewController class]]) {
-        [topViewController dismissViewControllerAnimated:NO completion:completion];
+        if (topViewController.isBeingDismissed) {
+            completion();
+        } else {
+            [topViewController dismissViewControllerAnimated:NO completion:completion];
+        }
     } else {
         completion();
     }