Increase protection testing for application credentials

This commit updates the application credential protection tests to
ensure users can't craft paths that bypass application credential
ownership checks.

Depends-On: https://review.opendev.org/c/openstack/keystone/+/760972
Change-Id: I7729190d42a6a7199553c5fc058e1b93eecb2068
Related-Bug: 1901207
1 file changed