Improve performance of login test and remove comments

What does this MR do?

Improves the performance of the login test and removes unnecessary comments from login tests.

Line 16 removed from qa/qa/specs/features/browser_ui/1_manage/login/log_in_spec.rb makes the test run 10 seconds faster.

More details in the commit messages.

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