Use or copy StoredWorkflow when copying step

Fixes https://sentry.galaxyproject.org/share/issue/509cadd762e749e1a782bb4806161ed3/:

```
AttributeError: 'NoneType' object has no attribute 'latest_workflow'
  File "starlette/applications.py", line 123, in __call__
    await self.middleware_stack(scope, receive, send)
  File "starlette/middleware/errors.py", line 186, in __call__
    raise exc
  File "starlette/middleware/errors.py", line 164, in __call__
    await self.app(scope, receive, _send)
  File "starlette_context/middleware/raw_middleware.py", line 92, in __call__
    await self.app(scope, receive, send_wrapper)
  File "starlette/middleware/base.py", line 189, in __call__
    with collapse_excgroups():
  File "contextlib.py", line 155, in __exit__
    self.gen.throw(typ, value, traceback)
  File "starlette/_utils.py", line 93, in collapse_excgroups
    raise exc
  File "starlette/middleware/base.py", line 191, in __call__
    response = await self.dispatch_func(request, call_next)
  File "galaxy/webapps/galaxy/fast_app.py", line 108, in add_x_frame_options
    response = await call_next(request)
  File "starlette/middleware/base.py", line 165, in call_next
    raise app_exc
  File "starlette/middleware/base.py", line 151, in coro
    await self.app(scope, receive_or_disconnect, send_no_error)
  File "starlette/middleware/exceptions.py", line 62, in __call__
    await wrap_app_handling_exceptions(self.app, conn)(scope, receive, send)
  File "starlette/_exception_handler.py", line 64, in wrapped_app
    raise exc
  File "starlette/_exception_handler.py", line 53, in wrapped_app
    await app(scope, receive, sender)
  File "starlette/routing.py", line 758, in __call__
    await self.middleware_stack(scope, receive, send)
  File "starlette/routing.py", line 778, in app
    await route.handle(scope, receive, send)
  File "starlette/routing.py", line 299, in handle
    await self.app(scope, receive, send)
  File "starlette/routing.py", line 79, in app
    await wrap_app_handling_exceptions(app, request)(scope, receive, send)
  File "starlette/_exception_handler.py", line 64, in wrapped_app
    raise exc
  File "starlette/_exception_handler.py", line 53, in wrapped_app
    await app(scope, receive, sender)
  File "starlette/routing.py", line 74, in app
    response = await func(request)
  File "fastapi/routing.py", line 278, in app
    raw_response = await run_endpoint_function(
  File "fastapi/routing.py", line 193, in run_endpoint_function
    return await run_in_threadpool(dependant.call, **values)
  File "starlette/concurrency.py", line 42, in run_in_threadpool
    return await anyio.to_thread.run_sync(func, *args)
  File "anyio/to_thread.py", line 56, in run_sync
    return await get_async_backend().run_sync_in_worker_thread(
  File "anyio/_backends/_asyncio.py", line 2144, in run_sync_in_worker_thread
    return await future
  File "anyio/_backends/_asyncio.py", line 851, in run
    result = context.run(func, *args)
  File "galaxy/webapps/galaxy/api/workflows.py", line 987, in refactor
    return self.service.refactor(trans, workflow_id, payload, instance or False)
  File "galaxy/webapps/galaxy/services/workflows.py", line 218, in refactor
    return self._workflow_contents_manager.refactor(trans, stored_workflow, payload)
  File "galaxy/managers/workflows.py", line 1963, in refactor
    refactored_workflow, action_executions = self.do_refactor(trans, stored_workflow, refactor_request)
  File "galaxy/managers/workflows.py", line 1947, in do_refactor
    action_executions = refactor_executor.refactor(refactor_request)
  File "galaxy/workflow/refactor/execute.py", line 77, in refactor
    refactor_method(action, execution)
  File "galaxy/workflow/refactor/execute.py", line 374, in _apply_upgrade_subworkflow
    content_id = trans.security.encode_id(stored_workflow.latest_workflow.id)
```

You can reproduce this by creating a subworkflow, renaming the parent
workflow and then attempting to update the subworkflow step.

lib/galaxy/model/__init__.py

@@ -8002,10 +8002,20 @@ def copy_to(self, copied_step, step_mapping, user=None):
             copied_step.annotations = annotations
 
         if subworkflow := self.subworkflow:
-            copied_subworkflow = subworkflow.copy()
-            copied_step.subworkflow = copied_subworkflow
-            for subworkflow_step, copied_subworkflow_step in zip(subworkflow.steps, copied_subworkflow.steps):
-                subworkflow_step_mapping[subworkflow_step.id] = copied_subworkflow_step
+            stored_subworkflow = subworkflow.stored_workflow
+            if stored_subworkflow and stored_subworkflow.user == user:
+                # This should be fine and reduces the number of stored subworkflows
+                copied_step.subworkflow = subworkflow
+            else:
+                # Can this even happen, building a workflow with a subworkflow you don't own ?
+                copied_subworkflow = subworkflow.copy()
+                stored_workflow = StoredWorkflow(
+                    user, name=copied_subworkflow.name, workflow=copied_subworkflow, hidden=True
+                )
+                copied_subworkflow.stored_workflow = stored_workflow
+                copied_step.subworkflow = copied_subworkflow
+                for subworkflow_step, copied_subworkflow_step in zip(subworkflow.steps, copied_subworkflow.steps):
+                    subworkflow_step_mapping[subworkflow_step.id] = copied_subworkflow_step
 
         for old_conn, new_conn in zip(self.input_connections, copied_step.input_connections):
             new_conn.input_step_input = copied_step.get_or_add_input(old_conn.input_name)