Unmute the mic toggle for emergency call

Also if the device is locked we shouldn't change the state of the
toggles, the system ui controls already prevent this but there's still a
workaround with adb.

Fixes: 186425724
Fixes: 186706938
Test: insert sim and \
      `adb shell cmd phone emergency-number-test-mode -a <phone-#>`
Change-Id: Iaf7f3413d8875bb6d909c828f354c1cd9229d01f