APIs for resources which don't have project_id still requires it in the API definition

[Slawek Kaplonski]

I discovered that while working on new default SG rules templates API: https://review.opendev.org/c/openstack/neutron/+/883246 but it seems it's the same for e.g. flavors: https://github.com/openstack/neutron-lib/blob/master/neutron_lib/api/definitions/flavors.py which have tenant_id defined in the API definiton even if policy don't really require it and it don't really belongs to any project.