Caveats when using ACL plugin

### Where is the problem?

https://docs.konghq.com/hub/kong-inc/acl/

### What happened?

We need to add this as a note for the plugin.

The ACL plugin will not work correctly for a service where the application registration plugin is already enabled. Either the application registration plugin should be enabled or the ACL plugin should be enabled.

### What did you expect to happen?

If you enable ACL plugin on a service where application registration plugin is already enabled then the consumer will not be able to access the resources even though they have been granted access. This is because application registration plugin will block them.

### Code of Conduct and Community Expectations

- [X] I agree to follow this project's Code of Conduct
- [X] I agree to abide by the Community Expectations

Start with the ACL plugin documentation page linked in the issue and review the existing notes around plugin compatibility. Add the stated caveat about using the ACL and application registration plugins together, then verify that the warning clearly explains the resulting access behavior.

Written by the indexing model from the issue text.