Show the same mpris player in the notification as in the app

Summary:
So switching (currently playing) players in the app will also switch the
notification.

Test Plan: Tested with two players playing at the same time, and switching between them.

Reviewers: #kde_connect, nicolasfella

Reviewed By: #kde_connect, nicolasfella

Subscribers: #kde_connect

Differential Revision: https://phabricator.kde.org/D11647

src/org/kde/kdeconnect/Plugins/MprisPlugin/MprisActivity.java

@@ -139,6 +139,10 @@ public class MprisActivity extends AppCompatActivity {
                                         }
                                         targetPlayer = mpris.getPlayerStatus(player);
                                         updatePlayerStatus(mpris);
+
+                                        if (targetPlayer.isPlaying()) {
+                                            MprisMediaSession.getInstance().playerSelected(targetPlayer);
+                                        }
                                     }
 
                                     @Override

src/org/kde/kdeconnect/Plugins/MprisPlugin/MprisMediaSession.java

@@ -405,4 +405,9 @@ public class MprisMediaSession implements SharedPreferences.OnSharedPreferenceCh
     public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
         updateMediaNotification();
     }
+
+    public void playerSelected(MprisPlugin.MprisPlayer player) {
+        notificationPlayer = player;
+        updateMediaNotification();
+    }
 }