Remove superfluous warning for printsequence

Print sequence can no longer be chosen per-object, so the warning that displays when you choose print sequence per-object is no longer necessary.

Contributes to issue CURA-458.

plugins/PerObjectSettingsTool/PerObjectSettingsPanel.qml

@@ -11,7 +11,6 @@ import UM 1.1 as UM
 Item {
     id: base;
     property int currentIndex: UM.ActiveTool.properties.SelectedIndex;
-    property string printSequence: UM.ActiveTool.properties.PrintSequence;
 
     UM.I18nCatalog { id: catalog; name: "cura"; }
 
@@ -25,14 +24,6 @@ Item {
 
         spacing: UM.Theme.sizes.default_margin.height;
 
-        Label {
-            width: UM.Theme.sizes.setting.width;
-            wrapMode: Text.Wrap;
-            text: catalog.i18nc("@label", "Per Object Settings behavior may be unexpected when 'Print sequence' is set to 'All at Once'.")
-            color: UM.Theme.colors.text;
-            visible: base.printSequence == "all_at_once"
-        }
-
         UM.SettingItem {
             id: profileSelection