jack: apply PIPEWIRE_PROPS after reading config

First apply config properties, then PIPEWIRE_PROPS.
We can set the node.latency in jack.conf

src/daemon/jack.conf.in

@@ -54,5 +54,6 @@ context.modules = {
 }
 
 jack.properties = {
+     #node.latency = 1024/48000
      #jack.merge-monitor  = false
 }