refactor: replace magic numbers with http status codes

What does this MR do?

replace magic numbers with http status codes.

From !534 (closed) for easier review

TODO

• I added the Changelog trailer (e.g. Changelog: feature) to the commits that need to be included in the changelog
• I added unit tests or they are not required
• I added acceptance tests or they are not required
• I added documentation (or it's not required)
• I followed code review guidelines
• I followed Go Style guidelines