Render labels using Text.QtRendering on OSX

Fonts were looking a bit to thick on when using `Text.NativeRendering`, so using `Text.QtRendering` instead. After this the font weight looks identical to figma (as far as I can see).

In this commit I also changed all `Label`'s to `UM.Label`'s and removed default properties where I could.

CURA-9154

resources/qml/ActionPanel/SliceProcessWidget.qml

@@ -5,7 +5,7 @@ import QtQuick 2.7
 import QtQuick.Controls 2.4
 import QtQuick.Layouts 1.3
 
-import UM 1.4 as UM
+import UM 1.5 as UM
 import Cura 1.0 as Cura
 
 
@@ -45,16 +45,13 @@ Column
         }
     }
 
-    Label
+    UM.Label
     {
         id: autoSlicingLabel
         width: parent.width
         visible: progressBar.visible
 
         text: catalog.i18nc("@label:PrintjobStatus", "Slicing...")
-        color: UM.Theme.getColor("text")
-        font: UM.Theme.getFont("default")
-        renderType: Text.NativeRendering
     }
     Item
     {
@@ -71,7 +68,7 @@ Column
             height: width
             status: UM.StatusIcon.Status.WARNING
         }
-        Label
+        UM.Label
         {
             id: label
             anchors.left: warningIcon.right
@@ -79,9 +76,6 @@ Column
             anchors.verticalCenter: parent.verticalCenter
             anchors.leftMargin: UM.Theme.getSize("default_margin").width
             text: catalog.i18nc("@label:PrintjobStatus", "Unable to slice")
-            color: UM.Theme.getColor("text")
-            font: UM.Theme.getFont("default")
-            renderType: Text.NativeRendering
             wrapMode: Text.WordWrap
         }
     }