Changes to Apply a template's design to a campaign.

added subschema #1 subschema #2 to the response body oneOf list for the response status 200

the response's body type changed from object to no type for status 200

removed the optional property campaign_id from the response with the 200 status

removed the optional property message from the response with the 200 status

removed the optional property template_id from the response with the 200 status

endpoint added