Hide Duo core settings for Duo Self-Hosted offline customers

What does this MR do and why?

Duo Core requires configuration with GitLab-hosted AI gateway, which is not an option for Duo Self-Hosted customers with an offline license. In this MR, the Duo Core setting is hidden for Duo Self-Hosted customers with an offline license.

References

Disable Core for Self-Hosted When No CC AIG Det... (#560442 - closed)

Screenshots or screen recordings

Offline license	Online license
Duo Core settings not rendered in page

How to set up and validate locally

Prerequisites:

You will need the following licenses from the provision team:

• Offline Ultimate/Pro
• Online Ultimate/Pro

Alternatively, you can apply the following patch to simulate offline license:

diff --git a/ee/app/presenters/admin/ai_configuration_presenter.rb b/ee/app/presenters/admin/ai_configuration_presenter.rb
index bad9454ba2a0..2f7754bc56cc 100644
--- a/ee/app/presenters/admin/ai_configuration_presenter.rb
+++ b/ee/app/presenters/admin/ai_configuration_presenter.rb
@@ -57,7 +57,7 @@ def beta_self_hosted_models_enabled
     end
 
     def has_offline_license?
-      ::License.current&.offline_cloud_license?
+      true
     end
 
     def can_manage_self_hosted_models?

Configure Duo Self-Hosted:

• Run GDK on non-SASS mode: GITLAB_SIMULATE_SAAS=0 gdk start
• Run the following setup script to get Duo Enterprise add on: GITLAB_SIMULATE_SAAS=0 bundle exec 'rake gitlab:duo:setup'

Steps:

1. Go to GitLab Duo admin settings page: /admin/gitlab_duo/configuration
2. With an online license: note Duo Core settings in the page
3. With an offline license: note Duo Core settings is not rendered

MR acceptance checklist

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