Disable admin API tests by default

Designate has deprecated the admin API and it is disabled by default in Designate. The tempest tests for it should also be disabled by default.
This patch corrects that mis-match between the tempest plugin and Designate default configurations.

Closes-Bug: #1982958
Change-Id: Ie854b23cb4e86439b427b13c0d769c538e8927e5
1 file changed