When node.target is set to contain a node's name, it is possible to run
into the situation where you have a sink and a source with the same name
(typically the case with module-loopback) and the sink has monitor ports,
so wireplumber may link the stream to the monitor of the sink instead of the
capture ports of the source

With this policy, if a stream really wants to link to the monitor of the sink,
it has to have the "stream.capture.sink" property set or specify the
target by id.