Replace html_safe with safe_format

What does this MR do and why?

Covers the suggestions from Simon:

can we use safe_format here? See note here on html_safe on translated content

(from !138337 (comment 1678812036))

As a result, we also dropped rubocop disabling and no longer relevant comments.

How to set up and validate locally

This is expected to be no-op change.
Just to be sure nothing is broken, we could do a manual check similar to !138337 (merged), but you don't need to enable FF - you should see "Beta" checkbox (second one) just fine.

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 #433994