Merge pull request #15711 from steveck-chung/DSDS-sim_switch_for_MMS

Bug 961938 - [DSDS][MMS] Switching data confirmation message will pop up twice r=julien
(cherry picked from commit 9497e89bbf6060d1a837a7ccbf396f8c359eb13b)

Conflicts:
	apps/sms/test/unit/thread_ui_test.js