Removes 'Job log message' from build trace

What does this MR do?

Removes 'No job log' message from JobsController#trace

Why was this MR needed?

On https://gitlab.com/gitlab-org/gitlab-ce/issues/44271 we wanted to display No job log message when the build has no trace. This is no longer necessary since we're now returning an image for this scenario (see https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/18278 for more context).

Besides the No job log message is also being repeated across the log https://gitlab.com/gitlab-org/gitlab-ce/issues/45625

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Tests added for this feature/bug
• Review
  • Has been reviewed by Backend
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• Internationalization required/considered
• End-to-end tests pass (package-and-qa manual pipeline job)

What are the relevant issue numbers?

Closes #45625 (closed)