Allow review-qa-smoke to fail in frontend MRs

What does this MR do?

It reverts the change made in !63140 (merged) (most likely accidentally) that enabled review-qa-smoke failure to block frontend MRs. Unfortunately, this job is still not reliable enough and can prevent multiple MRs from being merged. The work is being done in gitlab-com/www-gitlab-com#11568 (closed) to improve the job's reliability but it is not complete yet.

Does this MR meet the acceptance criteria?

Conformity

• I have included a changelog entry, or it's not needed. (Does this MR need a changelog?)
• I have added/updated documentation, or it's not needed. (Is documentation required?)
• I have properly separated EE content from FOSS, or this MR is FOSS only. (Where should EE code go?)
• I have added information for database reviewers in the MR description, or it's not needed. (Does this MR have database related changes?)
• I have self-reviewed this MR per code review guidelines.
• This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
• I have followed the style guides.
• This change is backwards compatible across updates, or this does not apply.