https://gitlab.com/gitlab-org/gitlab/-/merge_requests/79968 removed
`requirements_access_level` from `project_attributes.yml`, and
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/80667 re-added
this attribute to fix to fix a broken FOSS spec.

However, https://gitlab.com/gitlab-org/gitlab/-/merge_requests/80667
broke master because the attribute is used in EE. We now conditionally
add `requirements_access_level` as an expected key in EE and omit this
in FOSS builds.

Relates to https://gitlab.com/gitlab-org/gitlab/-/issues/352764