Changes to Update an existing display ad

added AdCohortsWritableAttributes to the measurementDisplayAd/allOf[#/components/schemas/DisplayAdUpdatableAttributes] request property allOf list

added the media type application/json for the response with the status 401

added the media type application/json for the response with the status 404

added the media type application/json for the response with the status 422

added the non-success response with the status 400

added the non-success response with the status 403

added the optional property measurementDisplayAd/allOf[#/components/schemas/DisplayAdWithParentAndChildren]/allOf[#/components/schemas/DisplayAdWithParent]/allOf[#/components/schemas/DisplayAd]/allOf[subschema #2]/cohorts to the response with the 200 status

added the optional property measurementDisplayAd/allOf[#/components/schemas/DisplayAdWithParentAndChildren]/allOf[#/components/schemas/DisplayAdWithParent]/allOf[subschema #2]/campaign/allOf[subschema #2]/pixel/brand/domain to the response with the 200 status