Switch DDS for MSIM emergency call

PhoneSwitcher now allows for the override of the DDS
in the event that it needs to be swapped before an
emergency call starts. This happens in DSDS situations
on devices where the modem does not support emergency
SUPL on the non-DDS.

Test: atest FrameworksTelephonyTests#PhoneSwitcherTest
Merged-In: I9b2e6eaf167411e3824f6bf909558d4fb2ccb8d2
Change-Id: I9b2e6eaf167411e3824f6bf909558d4fb2ccb8d2
(cherry picked from commit 19a9780b)