MJPEG IP Camera Device Requires still_image_url, username & password

Home Assistant core-2022.7.6 errors if no still_image_url, username or password is supplied even though these fields are marked as optional.

User input malformed: expected str for dictionary value @ data[‘still_image_url’]

Agree, I saw the similar behaviour with the Generic Cam integration too.
For now I made my changes by editing relevant files in . storage

Sounds like this issue:

If so, a fix PR is ready.