Report unexpected status codes as errors

[rdner]

The only expected code is 200, the rest should fail and the error message should contain the status code itself.

This is a follow up to #3834

[mergify]

This pull request does not have a backport label. Could you fix it @rdner? 🙏
To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-v./d./d./d is the label to automatically backport to the 7./d branch. /d is the digit
  NOTE: backport-skip has been added to this pull request.