Remove require byebug from code

Context

In !106885 (merged), we've introduced a require 'byebug', which is a development/test dependency.

It broke a few review-apps (internal link). See GCP logs (internal link).

It has the potential to break more production code (EDIT: it already broke some production deployments)

We'll track preventive actions in https://gitlab.com/gitlab-org/quality/engineering-productivity-infrastructure/-/issues/77

What does this MR do?

Remove this require from the codebase.

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.