media-session: don't bluez-autoswitch for suspended/idle/errored streams
E.g. skypeforlinux makes its input streams idle but does not destroy them, when no call is active.
Also add a missing node->obj->info != NULL check to check_passthrough, as ASAN picked up a crash there.
There seems to be some difficulty knowing when a stream is "corked", and which side is responsible for the stream node not running. If I understand correctly, this is as close as it gets currently, and probably is improvement over current situation. However, there will be issues if policy-node has already autoconnected the stream to somewhere that doesn't produce audio. But in that case it seems at least Skype has also other problems (can't close the call) that would also need to be addressed...
Edited by P V