FPII-2690:Ask for confirmation before importing from vcard

But only when vcard import is started from outside
the contacts application itself.

Test: Manually confirmed the following behavior

1. When there is 0 or 1 writable contacts providing
   account on the device:
  - Importing contacts from the contacts app itself
    DOES NOT SHOW the new confirmation dialog.
  - Sending a vcard to contacts from another application
    DOES SHOW the new confirmation dialog.

2. When there are 2 or more writable contacts providing
   accounts on the device:
  - Importing contacts from the contacts app itself
    DOES NOT SHOW the new confirmation dialog, instead the
    existing account picker dialog is displayed.
  - Sending a vcard to contacts from another application
    DOES NOT SHOW the new confirmation dialog, instead the
    existing account picker dialog is displayed.

Change-Id: I3c32bef6dbc04f22c39428c5d00d7d63a1c37126
4 files changed