Call machine func (#9191)

* Force label printing to background worker

* Refactor "check_reload" state of machine registry

- In line with plugin registry
- More work can be done here (i.e. session caching)

* Better handling of call_plugin_function

* Wrapper for calling machine function

* Use AttributeError instead

* Simplify function offloading

* Check plugin registry hash when reloading machine registry

* Cleanup

* Fixes

* Adjust unit test

* Cleanup

* Allow running in foreground if background worker not running

* Simplify call structure

src/frontend/src/tables/machine/MachineListTable.tsx

@@ -514,7 +514,7 @@ export function MachineListTable({
   }, [machineDrivers, createFormMachineType]);
 
   const createMachineForm = useCreateApiFormModal({
-    title: t`Add machine`,
+    title: t`Add Machine`,
     url: ApiEndpoints.machine_list,
     fields: {
       name: {},