Added forcefull property changed if perobjectsettings extruder was changed

CURA-2319

plugins/PerObjectSettingsTool/PerObjectSettingsPanel.qml

@@ -260,6 +260,14 @@ Item {
                             storeIndex: 0
                             removeUnusedValue: false
                         }
+
+                        // If the extruder by which the object needs to be printed is changed, ensure that the
+                        // display is also notified of the fact.
+                        Connections
+                        {
+                            target: extruderSelector
+                            onActivated: provider.forcePropertiesChanged()
+                        }
                     }
                 }
             }