refactor: make sure updateAppWidget is not called twice at the same time
Description
Make sure updateAppWidget is not called twice at the same time
Screenshots
Technical details
Sentry has weird NullPointException & ArrayIndexOutOfBoundsException.
Since a lot of stuffs are done in the BroadcastReceiver.onReceived() callback and it could be called twice quite fast, let's make sure it is a least thread safe.