Add Beta to Custom Refresh Sandbox

With many exciting new features and interface updates, comes the need to stage and test items before rolling them out to the wider team. The rollout of "Home" is a good example. It would be great if we had the ability to stage the update in the custom refresh sandbox and share it with the team to optimize it prior to a roll out. By making Beta only available in the preview, we are at the mercy of the automated syncing.