Use coroutine scope instead of using runBlocking for rejoining

[skydoves]

🎯 Goal

Use coroutine scope instead of using runBlocking for rejoining

🛠 Implementation details

Since runBlocking blocks the entire Android main thread and occupies it until the coroutine scope is completed, it can lead to ANRs or prevent the UI from rendering properly.

[skydoves]

Closing - The prepareRejoin() function will eventually be invoked inside the worker thread from the call site; the consideration will not happen for now.