Resolve "`gitlab-rake gitlab:cleanup:orphan_job_artifact_files DRY_RUN=false` is not removing artifacts"

What does this MR do?

Fixes bug that prevents users from cleaning up orphaned artifacts

The trailing newline was actually causing the FileUtils.rm_rf() call to look like it was working, but was in fact not deleting at all.

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers

Closes #32534 (closed)