SimpleMessageDialog.qml: use var for buttonRoles

In practice, the QML engine fails to set arrays of non-variant types
when creating QML components dynamically.

Gitlab: #1934
Change-Id: I5e9c0e73dd35c088bdaf070e04cf73c009ea9099

src/app/commoncomponents/SimpleMessageDialog.qml

@@ -35,7 +35,7 @@ BaseModalDialog {
     property var buttonStyles: []
     property string infoText: ""
     property var innerContentData: []
-    property int buttonRoles: []
+    property var buttonRoles: []
 
     function openWithParameters(title, info = "") {
         root.title = title;