service: do not emit clientDisconnected signal on playbin reset

The playbin can get reset for many other reasons (such as missing
codecs) and the client must still be able to control the backend and
choose another file to play.

The clientDisconnected() signal is now unused, but let's keep it in case
we find real cases where the playbin can detect that the client
disconnected.

src/core/media/gstreamer/playbin.cpp

@@ -209,17 +209,15 @@ gstreamer::Playbin::~Playbin()
 
 void gstreamer::Playbin::reset()
 {
-    MH_INFO("Client died, resetting pipeline");
-    // When the client dies, tear down the current pipeline and get it
+    MH_INFO("Resetting pipeline");
+    // Tear down the current pipeline and get it
     // in a state that is ready for the next client that connects to the
     // service
 
     // Don't reset the pipeline if we want to resume
     if (player_lifetime != media::Player::Lifetime::resumable) {
         reset_pipeline();
     }
-    // Signal to the Player class that the client side has disconnected
-    Q_EMIT clientDisconnected();
 }
 
 void gstreamer::Playbin::reset_pipeline()