Qt5->Qt6: Usee key-constants namespace.

part of CURA-8591

plugins/SupportEraser/SupportEraser.py

@@ -31,7 +31,7 @@ import numpy
 class SupportEraser(Tool):
     def __init__(self):
         super().__init__()
-        self._shortcut_key = Qt.Key_E
+        self._shortcut_key = Qt.Key.Key_E
         self._controller = self.getController()
 
         self._selection_pass = None

resources/qml/Cura.qml

@@ -152,7 +152,7 @@ UM.MainWindow
         //DeleteSelection on the keypress backspace event
         Keys.onPressed:
         {
-            if (event.key == Qt.Key_Backspace)
+            if (event.key == Qt.Key.Key_Backspace)
             {
                 Cura.Actions.deleteSelection.trigger()
             }