Enable Target Users Across All Feature Flag Environment Scopes

What does this MR do?

If a feature flag scope Status is disabled, and there are user ids in the list of Target Users, then return a feature to unleash clients that is enabled with a single userWithId strategy containing the list of user ID's.

For example, in the scenario shown below:

The Production environment will return a feature to Unleash that looks like this:

    {                                                              
      "name": "myfeature",                                            
      "description": "Turn the feature on and off",                 
      "enabled": true,                                             
      "strategies": [                                              
        {                                                          
          "name": "userWithId",                                    
          "parameters": {                                          
            "userIds": "jagood,dosuken123"                         
          }                                                        
        }                                                          
      ]                                                            
    }

Related to https://gitlab.com/gitlab-org/gitlab-ee/issues/14011

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team