message: [metal3] Make maintenance optional in inventory item
  If the maintenance operator isn't available, the item will still render.
diff: @@ -105,6 +105,7 @@ const plugin: Plugin<ConsumedExtensions> = [
  isList: true,
  kind: referenceForModel(NodeMaintenanceModel),
  prop: 'maintenaces',
  + optional: true,
  },
  ],
  model: BareMetalHostModel,
  