Fix doc and changelog API response for orphaned addons

[mdegat01]

Proposed change

Follow-up to #5064 . It appears orphaned addons return 400 responses to /changelog that the frontend cannot interpret. While digging I noticed that the /documentation API has the same problem, it just hasn't come up yet (probably because update entities do not hit it in the background like they do with the changelog).

Changed both these APIs so they go back to returning 200 responses with the error as text. As noted in the other PR, we should really handle this differently. Although in this case I'm not sure a 404 makes sense since this is a bit odd. Still it would be nice to have the API correctly report an error and the frontend show the appropriate text rather then having supervisor return error text to display to users.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New feature (which adds functionality to the supervisor)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes Could not fetch changelog errors not fixed in 2024.05.1 #5076
• This PR is related to issue:
• Link to documentation pull request:
• Link to cli pull request:

Checklist

• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist
• The code has been formatted using Ruff (ruff format supervisor tests)
• Tests have been added to verify that the new code works.

If API endpoints of add-on configuration are added/changed:

• Documentation added/updated for developers.home-assistant.io