DS Hidden Region leaking into other layouts

Problem/Motivation

When using Layout builder with "Hidden region" enabled in Layout Builder extras, the DS Hidden region displays as an option inside of all layout builder sections event though those sections don't use the DsLayout.

Proposed resolution

The DS Hidden region should only be present on layouts using the DsLayout class. Furthermore, DS layouts should be able to opt-in to the DS Hidden region rather than having it as a global setting.