Only allow UTF-8 Build IDs with <= 255 chars

[carlydf]

What changed?

Only allow UTF-8 Build IDs with <= 255 chars

Why?

Because the storage for build ids is VARCHAR(255), and non-UTF-8 would be super weird and probably a mistake.

How did you test it?

Functional test. Could not test in versioning unit tests because this is enforced in the frontend.

Potential risks

Documentation

Communicated with docs team

Is hotfix candidate?