Add emergency SUPL DDS switch for DP only roaming partners

Although an operator may support control plane fallback for
emergency SUPL requests, a roaming operator may not. Define
a new CarrierConfig for known roaming partners of an operator
that do not support CP fallback and in those cases, perform
a DDS switch before placing the emergency call if possible.

Bug: 144383368
Test: manual; atest TeleServiceTests
Merged-In: I7bd81ddb9730cd2cff7c246f0321af090eb6b2c6
Change-Id: I7bd81ddb9730cd2cff7c246f0321af090eb6b2c6
9 files changed