Do not request sinks list

Rely on it being sent at connect and on any update.

It requires this desktop app change to be merged and released, since we
were not sending the list at connect time before:
https://invent.kde.org/network/kdeconnect-kde/-/merge_requests/763

src/org/kde/kdeconnect/Plugins/SystemVolumePlugin/SystemVolumeFragment.java

@@ -100,7 +100,7 @@ public class SystemVolumeFragment
         }
         this.plugin = plugin;
         plugin.addSinkListener(SystemVolumeFragment.this);
-        plugin.requestSinkList();
+        sinksChanged();
     }
 
     private void disconnectFromPlugin(final String deviceId) {

src/org/kde/kdeconnect/Plugins/SystemVolumePlugin/SystemVolumePlugin.java

@@ -113,12 +113,6 @@ public class SystemVolumePlugin extends Plugin {
         getDevice().sendPacket(np);
     }
 
-    void requestSinkList() {
-        NetworkPacket np = new NetworkPacket(PACKET_TYPE_SYSTEMVOLUME_REQUEST);
-        np.set("requestSinks", true);
-        getDevice().sendPacket(np);
-    }
-
     @Override
     public @NonNull String[] getSupportedPacketTypes() {
         return new String[]{PACKET_TYPE_SYSTEMVOLUME};

src/org/kde/kdeconnect/Plugins/SystemVolumePlugin/SystemVolumeProvider.kt

@@ -155,21 +155,21 @@ class SystemVolumeProvider private constructor(plugin: SystemVolumePlugin) :
         return sink != null
     }
 
-    fun startListeningForSinks() {
-        systemVolumePlugin.addSinkListener(this)
-        systemVolumePlugin.requestSinkList()
-    }
-
     fun release() {
         stopListeningForSinks()
         stateListeners.clear()
         currentProvider = null
     }
 
+    private fun startListeningForSinks() {
+        systemVolumePlugin.addSinkListener(this)
+        sinksChanged();
+    }
+
     private fun stopListeningForSinks() {
         for (sink in systemVolumePlugin.sinks) {
             sink.removeListener(this)
         }
         systemVolumePlugin.removeSinkListener(this)
     }
-}
+}