Add Code Suggestion to the DAP supported features for self-hosted models

What does this MR do and why?

Related to #593893 (closed). Currently for self-hosted models, Code Suggestions features is not part of the DAP features. That mean that not all users without an assigment has access to this feature once a external model is pinned.

You also can't use the Code Suggestions feature.

This is considered a bug. See this thread for context.

This MR fixes that by considering that Code Suggestions features is not part of the DAP features. This means that when the license is online, everyone has access to code suggestions feature even if the model that support the feature is self-hosted without an self-hosted add-on.

How to set up and validate locally

• Set up an online license to your instance
• Set an Self-hosted model for both Code Generation and Code Completion in /admin/gitlab_duo/model_selection
  • If you don't have any self-hosted model setup. Do that first /admin/gitlab_duo/model_selection/models
• Go to /admin/gitlab_duo and run the health check, the Code Suggestions probe should pass

You will be able to use the Code Suggestions feature.

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Related to #593893 (closed)