qml: Add DISABLED state to ContinueButton

Author: johnny9

src/qml/controls/ContinueButton.qml

@@ -32,6 +32,12 @@ Button {
         radius: 5
 
         states: [
+            State {
+                name: "DISABLED"; when: !root.enabled
+                PropertyChanges { target: bg; color: Theme.color.neutral2 }
+                PropertyChanges { target: bg; border.color: Theme.color.neutral2 }
+                PropertyChanges { target: root; textColor: Theme.color.neutral5 }
+            },
             State {
                 name: "PRESSED"; when: root.pressed
                 PropertyChanges { target: bg; color: backgroundPressedColor }