feat: add alpha availability hint to migration guide (#3459)

docs/apis-tools/tasklist-api-rest/migrate-to-zeebe-user-tasks.md

@@ -28,6 +28,10 @@ In this guide, you will learn:
 - How to estimate the impact on a project.
 - The steps you need to take for a successful migration without interrupting your operations.
 
+:::info
+The [Zeebe-based user task implementation](/components/modeler/bpmn/user-tasks/user-tasks.md) is not yet supported in the user interface in version 8.5-alpha2, and ignored in search result sets. However, they can be accessed via the API. To use the Tasklist user interface, use the [job worker-based implementation](/components/modeler/bpmn/user-tasks/user-tasks.md#job-worker-implementation).
+:::
+
 ## Decide on your migration path
 
 Zeebe user tasks require migration of the user tasks in both your diagrams and the task API.