Qt: fix play button state after toolbar customization

Close #10850

modules/gui/qt4/components/controller.cpp

@@ -241,6 +241,7 @@ QWidget *AbstractController::createWidget( buttonType_e button, int options )
         CONNECT_MAP_SET( playButton, PLAY_ACTION );
         CONNECT( this, inputPlaying( bool ),
                  playButton, updateButtonIcons( bool ));
+        playButton->updateButtonIcons( THEMIM->getIM()->playingStatus() == PLAYING_S );
         widget = playButton;
         }
         break;

modules/gui/qt4/components/controller_widget.hpp

@@ -52,7 +52,7 @@ class QAbstractSlider;
 class PlayButton : public QToolButton
 {
     Q_OBJECT
-private slots:
+public slots:
     void updateButtonIcons( bool );
 };