Fixed for r58099 per CR:

Fixed for r58099 per CR:
* Only clicktrack local, domain-relative URLs
* Validate redirect URL in ApiClickTracking with the same condition used in ClickTracking.js (local, domain-relative)
* Remove call to nonexistent function OutputPage::enable()
* Add functionality for disabling API output and use this after setting up the redirect. This fixes the issue where the body of the redirect contained an API response in xmlfm form
at; the body is now empty.