Updates a campaign's editor data, including the content and subject line.
The composerDataJson format must match the campaign's existing campaignEditorType. Passing a mismatched format causes a silent failure when sending or previewing the campaign.
You can only call this method when authenticated as a Wix app or Wix user identity.
This method doesn't return any custom errors, but may return standard errors. Learn more about standard Wix errors.