Improvements and fixes for GettingStarted logging:

* Add funnel to navbar-* events
* Change returnto to use welcomepage-click and log it for both test and control
* Update schema ID
* Fix bucket on page-save-attempt

Change-Id: Ie59c7cede8076aea4cd5aca8e8eaac07f8e8c1fe
Merge "Improvements and fixes for GettingStarted logging:"