Gracefully handle reconnection failure on WebSocket

[TimoPtr]

Originally posted by @TimoPtr in https://github.com/home-assistant/android/pull/5219#discussion_r2044438484

Currently if the connection fail we try to reconnect and re-subscribe to the entity that were previously registered. But if it fails to reconnect then nothing will happen and even if the connection is re-open later it won't resubscribe.