Qt: update the Win32 thumbnail after fullscreen

Close #10514

(cherry picked from commit 291b79a14742361914bdc71048f291c14c797661)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/gui/qt4/main_interface.cpp

@@ -755,6 +755,9 @@ void MainInterface::setVideoFullScreen( bool fs )
          * qt-fullscreen-screennumber is forced) */
         setMinimalView( b_minimalView );
         setInterfaceFullScreen( b_interfaceFullScreen );
+#ifdef _WIN32
+        changeThumbbarButtons( THEMIM->getIM()->playingStatus() );
+#endif
     }
     videoWidget->sync();
 }