Describe the bug
Sentinel solution for GitHub/ Microsoft Sentinel - Continuous Threat Monitoring for GitHub has been in preview stage for over 2 years based on commit history. Customers are not wanting to deploy the solution as it has been in a preview state and policies restrict loading preview to prod environments.

Solution link
https://github.com/Azure/Azure-Sentinel/tree/master/Solutions/GitHub

Steps to reproduce the behavior:

1. Go to content hub and search GitHub
2. Microsoft Sentinel - Continuous Threat Monitoring for GitHub will show up and have a preview flag associated to it.
3. Solution has had a number of commits over the past 2 + years and preview flag were never removed.
   

Expected behavior

1. Validate but remove the Preview flag in the solution.
2. Remove (Preview) for analytic rules