Remove unused controls imports

plugins/SimulationView/LayerSlider.qml

@@ -1,10 +1,8 @@
-// Copyright (c) 2017 Ultimaker B.V.
+// Copyright (c) 2021 Ultimaker B.V.
 // Cura is released under the terms of the LGPLv3 or higher.
 
 import QtQuick 2.2
-import QtQuick.Controls 1.2
 import QtQuick.Layouts 1.1
-import QtQuick.Controls.Styles 1.1
 
 import UM 1.0 as UM
 import Cura 1.0 as Cura

plugins/SimulationView/PathSlider.qml

@@ -1,10 +1,8 @@
-// Copyright (c) 2017 Ultimaker B.V.
+// Copyright (c) 2021 Ultimaker B.V.
 // Cura is released under the terms of the LGPLv3 or higher.
 
 import QtQuick 2.2
-import QtQuick.Controls 1.2
 import QtQuick.Layouts 1.1
-import QtQuick.Controls.Styles 1.1
 
 import UM 1.0 as UM
 import Cura 1.0 as Cura