Forbid setting NO_ACCESS to unprotect-access-level for protected branches

Why are we doing this work

As described #345277 (closed)

Users have the ability via the protected branch api to set unprotect-access-level to NO_ACCESS. This creates a problem where no users are able to unprotect a protected branch.

During discussion in #345277 (comment 1254166347) it was decided to remove the NO_ACCESS option for unprotect-access-level, while not modifying/breaking unprotect-access-level values which are currently set to NO_ACCESS.

Relevant links

#345277 (closed)

Non-functional requirements

  • Documentation: specify that NO_ACCESS is no longer available for unprotect-access-level
  • Testing: confirm that this change does not effect protected branches which currently have NO_ACCES set.