Bug 935041 - Investigate test_sms_add_contact failure, resolve and re-enable the test

Conflicts:
	tests/python/gaia-ui-tests/gaiatest/apps/contacts/app.py
	tests/python/gaia-ui-tests/gaiatest/tests/functional/messages/test_sms_add_contact.py
Merge pull request #13392 from bobsilverberg/v1.2935041

Bug 935041 - Investigate test_sms_add_contact failure, resolve and re-enable the test