Updates frontend code and specs to allow for the new
feature flag

In the job log, if the user clicks the section title
the job log section will be collapsed

Using the sed script from
https://gitlab.com/gitlab-org/gitlab-ce/issues/59758

We've already migrated all the legacy artifacts to the new realm,
which is ci_job_artifacts table.
It's time to remove the old code base that is no longer used.

When backend sends HTML it requires frontend to append it to the DOM causing
XSS vulnerabilities. By removing the `<br>` we avoid those vulnerabilities

When backend sends HTML it requires frontend to append it to the DOM causing
XSS vulnerabilities. By removing the `<br>` we avoid those vulnerabilities