broadcaster: Allow double resume while broadcasting

It looks like some drivers e.g. offloader may call multiple resume
request even if previous one were confirmed.
Allow double resume while there are already established broadcast
streams.

Bug: 389170834
Bug: 347204335
Flag: com.android.bluetooth.flags.leaudio_big_depends_on_audio_state
Test: atest bluetooth_test_broadcaster
Change-Id: I7d07b5e30ea5ae1dded666b97758731dfbfa9eb0