During first attempt of the Secure RBAC implementation [1] to
function model_query_scope_is_project() there was added check
which was checking if context.system_scope is "all" in case when
scope enforcement was enabled. It was like that because that meant
that it is SYSTEM_* persona context (e.g. SYSTEM_ADMIN).
This is not needed now as later it was agreed to have only one ADMIN
user which will still behave like old, "legacy" ADMIN user.
[1] https://review.opendev.org/c/openstack/neutron-lib/+/781075
Closes-bug: #1996150
Change-Id: If3a97c4d3a0f4cb6b4d06434f74cbe9d933a07a4
91759b17ea