feat(code suggestions): show license status

Description

This MR uses the new GraphQL endpoint (gitlab!141617 (merged)) to show the user whether they have a code suggestion license.

Related Issues

Resolves #1232 (closed)

How has this been tested?

1. Add the feature flag to your settings.json "gitlab.featureFlags.codeSuggestionsLicensePolicy": true,

2. Check what is your license status:

   • https://gitlab.com/-/graphql-explorer

   • query aiAccess {
       currentUser {
        duoCodeSuggestionsAvailable
       }
     }

3. If the GraphQL endpoint returns true then you have a license

   1. If you have a license, use a different user (I have a private test user)
   2. For this user, generate access token with api scope https://gitlab.com/-/user_settings/personal_access_tokens
   3. Remove existing users from VS Code GitLab: Remove Account command
   4. Add the new user to VS Code GitLab: Add Account command

4. Go to a supported source file (e.g. TypeScript) and see the status bar tell you that you don't have a license

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation
• Chore (Related to CI or Packaging to platforms)
• Test gap