Add required product approvals and clean up

Cynthia "Arty" Ngrequested to merge
product-14293 into master

Adds PLT and product leaders group as required approvals for categories and features to prevent merging without required approvals as per https://handbook.gitlab.com/handbook/product/categories/#changes . This also helps with our compliance as we'll be using the files for https://gitlab.com/gitlab-com/Finance-Division/finance/-/issues/6499 (internal).

Also:

  1. removes product leaders group from optional approvals except section-level direction pages.
  2. ensures egroup is listed for all required approvals.
Edited by Cynthia "Arty" Ng

Merge request reports