Description

Steps to reproduce (step by step instructions, with links, commands and necessary data to reproduce the error)

1. bring up the MW stack locally using docker-compose
2. in a browser, navigate to http://localhost:8080/wiki/Special:ApiSandbox
3. run the test called "Invoke user-defined validation function implemented in Python."

Observed behavior

• there is no error; the input object is returned intact

Expected behavior/Acceptance criteria (returned value, expected error, performance expectations, etc.)

• there should be an error

Completion checklist

• we will fix the validation workflow in the function-orchestrator, which is probably what's causing this error
• we will run this test (and several more of the sandbox examples) in our integration tests in order to catch similar regressions
• Before closing this task, review one by one the checklist available here: https://www.mediawiki.org/wiki/Abstract_Wikipedia_team/Definition_of_Done#Back-end_Task/Bug_completion_checklist