Follow-up from "Add section for permanent experiment implementation concerns"

The following discussion from !74106 (merged) should be addressed:

• @dreedy started a discussion:

  ## Experiment Promotion Concerns
  
  _Items to be considered if candidate experience is to become a permanent part of GitLab_
  
  <!-- 
  Add a list of items raised during MR review or otherwise that may need further thought/consideration
  before becoming permanent parts of the product.