Add timing data for the first transaction

This doesn't quite tell us about the user's first interaction with
VE (if they open a dialog, for instance, it could be minutes before
that results in a transaction), but it's a good start.

Bug: T76524
Change-Id: I6bac987332802d7363ed65a471b2b1ece67086d8
Merge "Add timing data for the first transaction"