Mms: fix copying sim messages from sim to phone with single sim

A phone_id column is expected to be populated in the cursor, but it will
never be returned with single-sim devices which use the regular ICC_URI.

Change-Id: I53a603505b89f5c4244002f038a23edb8ae28718
Signed-off-by: Roman Birg <roman@cyngn.com>