Merge pull request #1463 from OneSignal/fix/IAM_preview_NPE_3.X.X

Fix IAM preview message id NPE

Author: nan-li

OneSignalSDK/onesignal/src/main/java/com/onesignal/OSInAppMessageController.java

@@ -612,8 +612,8 @@ private void dismissCurrentMessage(@Nullable OSInAppMessage message) {
 
         inAppMessageShowing = false;
         synchronized (messageDisplayQueue) {
-            if (messageDisplayQueue.size() > 0) {
-                if (message != null && !messageDisplayQueue.contains(message)) {
+            if (message != null && !message.isPreview && messageDisplayQueue.size() > 0) {
+                if (!messageDisplayQueue.contains(message)) {
                     OneSignal.onesignalLog(OneSignal.LOG_LEVEL.DEBUG, "Message already removed from the queue!");
                     return;
                 } else {