Marks a pricing plan as the primary pricing plan. When viewing pricing plans on a site, the primary plan is highlighted with a customizable ribbon. Only a single plan can be marked as a primary plan at any given time. If there is an existing plan marked as primary, calling Make Plan Primary causes the existing primary plan to lose its primary status.
You can only call this method when authenticated as a Wix app or Wix user identity.
ID of the pricing plan to set as the primary plan.