Don't allow importing contacts to accounts passed in by intent unless it is valid

Test: Manual installing PoC app and running through repro steps
Bug: 278556954
(cherry picked from commit 7d35065b)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:c8c222bc6cfb29c12f540fe404c259760b454f1a)
Merged-In: If36958e9ed2e9423b9c67ac635c9a7f65469e917
Change-Id: If36958e9ed2e9423b9c67ac635c9a7f65469e917