[AA+ Search] Add logging for header search icon tapping events.

Logging example for the search icon tapping event: https://paste.googleplex.com/4809431536631808

Bug: 198507048
Test: tested with AiAi apk with search icon sent as child of header.
Change-Id: Ibbaec61b93c30a99ea2ffef8d7342490ba37335d
3 files changed