Fix bug samsung A21s

This MR is raised to resolve the bugs found in Samsung A21s. Both bugs were triggered at onStop() function. The onStop function is used to unregister the Broadcast Receiver.

Earlier, Broadcast receiver was created on onResume function and removed on onStop. Although, it was working fine on other devices. After some research, I found that all Broadcast Receiver should be created on onStart function as per Android official documentation. https://developer.android.com/guide/components/activities/process-lifecycle

I have made the required changes in this MR. I hope, this fix can resolve the bugs on Samsung A21s.

Fix #44 (closed) #45