Corner case bug: admin metadata and policies still present, when all admins removed from application configuration.

Steps to reprodce:
1. Set up and execute plugin with admins

permission:
enabled: true
rbac:
database:
enabled: true
admin:
users:

• name: user:default/some-user

1. Remove all admins from configuration:

permission:
enabled: true
rbac:
database:
enabled: true
admin:
users: []

3: Check database data: admin group policy for user user:default/some-user
still present.