Adds license check for AI Agents
What does this MR do and why?
Ai agents is an ultimate feature but the license wasn't being checked.
How to set up and validate locally
Example below:
- Enable the feature flag
Feature.enable(:agent_registry) - Create a group without access to ultimate (https://docs.gitlab.com/ee/development/ee_features.html#simulate-a-saas-instance)
- Navigate to /-/ml/agents, it should 404
- Enable Ultimate for the project, and refresh. It should show the page now