fix(Push): add null checker at LeanplumPushService.openNotification method.

Author: Enuviel

AndroidSDK/src/com/leanplum/LeanplumPushService.java

@@ -408,6 +408,9 @@ static void openNotification(Context context, Intent intent) {
 
     if (shouldStartActivity) {
       Intent actionIntent = getActionIntent(context);
+      if (actionIntent == null) {
+        return;
+      }
       actionIntent.putExtras(notification);
       actionIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK);
       context.startActivity(actionIntent);