Fix Bug with Self-Hosted Beta Features

A significant underlying issue was identified during troubleshooting of Self-Hosted beta features in this issue.

All Self-Hosted features currently in beta don't work properly in self-hosted environments due to permission check issues. This affects both air-gapped and online instances. The problem occurs because:

• The system doesn't correctly use self_hosted_models as the service name during permission checks
• Features like /include command and "Explain Vulnerability" don't appear or function properly

A fix has been proposed in merge request #190710 and !190817 (merged) to address these permission issues.

Definition of Done

• Replicate a customer environment for Self-Hosted on self-managed
• Validate that all beta features are working as expected, to include:
  • Root Cause Analysis
  • Vulnerability Explanation
  • Vulnerability Reoslution
  • Discussion Summary
  • GL Duo for the CLI
  • Summarize Code Review
  • MR Commit Message Generation
  • Summarize New MR
  • Troubleshoot