Cannot direct dial or video call from Dialer search results.

- Change made in partner CL introduced a regression in dialing from
the search results:
https://partner-android-review.googlesource.com/#/c/206297/
The problem with that change is that it was intended to ensure that the +
was not stripped off when dialing from the dial pad.  It had the
unintential impact of rendering direct dial from the search box inoperative.
since mAddToContactNumber was null in this case.

Bug: 20068746
Change-Id: Ic3a75ccf00164e7c865cc633a6a16d1699227ed2