AudioDeviceBroker: strengthen setcommunicationDevice implementation

Move all logic accessing the communication device clients and other states
to the message handler: this removes the possibility of nested conflicting
communication route requests to read or modify states concurrently.

Bug: 238137937
Test: atest AudioCommunicationDeviceTest
Test: atest AudioManagerTest
Change-Id: Iff4f727e140812ad5a46fe960e19b55728adb110