Zone Manager: Update layer handling to use UIOrder instead of Seq

Fixes https://gitlab.com/kicad/code/kicad/-/issues/19482

pcbnew/zone_manager/model_zones_overview_table.cpp

@@ -143,7 +143,7 @@ void MODEL_ZONES_OVERVIEW_TABLE::GetValueByRow( wxVariant& aVariant, unsigned aR
             layers.Add( m_pcb->GetLayerName( layer ) );
 
         aVariant << wxDataViewIconText( wxJoin( layers, ',' ),
-                                        MakeBitmapForLayers( cur.GetLayerSet().Seq(),
+                                        MakeBitmapForLayers( cur.GetLayerSet().UIOrder(),
                                                              *m_PCB_FRAME->GetColorSettings(),
                                                              bmSize ) );
         break;

pcbnew/zone_manager/pane_zone_viewer.cpp

@@ -145,7 +145,7 @@ void PANE_ZONE_VIEWER::ActivateSelectedZone( ZONE* aZone )
 
     const PCB_LAYER_ID firstLayer = aZone->GetFirstLayer();
 
-    for( PCB_LAYER_ID layer : aZone->GetLayerSet().Seq() )
+    for( PCB_LAYER_ID layer : aZone->GetLayerSet().UIOrder() )
     {
         wxString layerName =
                 m_pcbFrame->GetBoard()->GetLayerName( static_cast<PCB_LAYER_ID>( layer ) );