RuboCop: Enable previously disabled cop Lint/MissingCopEnableDirective

What does this MR do and why?

Describe in detail what your merge request does and why.

Re-enables the Lint/MissingCopEnableDirective cop as requested in #369268 (closed).

How to set up and validate locally

bin/rake rubocop:todo:generate[Lint/MissingCopEnableDirective]

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

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

Related to #369268 (closed)