this event extends the bound_id event and sends the global properties as
well.
This can be used to get the object.serial, for example.
It can also be used in the future to let the server generate unique
property values, like the node.name, and let the client know about the
new property value.
Add a module for a fallback dummy sink, which appears dynamically when
no other sinks are present.
Enable it for pipewire-pulse, because Pulseaudio will also show
dynamically a dummy sink.