Don't just forward the tag and latency events to the follower but let
the audioconvert aggregate and emit the updated tag/latency event
that is then configured on the follower.
When using the DSP mode of the audioconvert, this results in an
accumulated latency/tag from all the DSP ports instead of just
the last DSP port param update.
Put properties with media. prefix in tags in pw-cat.
ebeae802ad