## Description:
Passing in a configuration for the embedded MQTT server has been broken for a while. This fixes that. See related issue number for further details.
**Related issue (if applicable):** fixes#18228
## Checklist:
- [x] The code change is tested and works locally.
- [x] Local tests pass with `tox`. **Your PR cannot be merged unless tests pass**
- [x] There is no commented out code in this PR.