Add validation for having pending operations while app installation

         }
     }
 
+    private <T> void validatePendingAppSubscription(List<Device> devices, SubscribingDeviceIdHolder subscribingDeviceIdHolder) throws BadRequestException{

+               String msg = "All devices in the subscription have pending operations for this application.";
+                log.error(msg);
+                throw new BadRequestException(msg);
+            }