Fix all funnels to only fire 'start' events the first time they're created.

User funnels should only fire 'start' events corresponding to user intent, not
to the technical state of whether the activity was destroyed and then
recreated from its savedInstanceState.

This patch fixes all remaining activities so they only fire 'start' events the
first time the activities are created, to figure out true bounce rates.

Change-Id: Icbe1cab39bbda528a795e834196d201146ca9446