Qt: fix gototime focus

Close #6670
(cherry picked from commit 82694751a23d72056038800fc4e508377fed5c50)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/gui/qt4/dialogs/gototime.cpp

@@ -89,6 +89,7 @@ void GotoTimeDialog::toggleVisible()
         timeEdit->setTime( timeEdit->time().addSecs( i_time / 1000000 ) );
     }
     QVLCDialog::toggleVisible();
+    activateWindow ();
 }
 
 void GotoTimeDialog::cancel()