Read preferred IKE protocol from carrier config am: 4c195ab20e am: c294baaebb am: 591a5d4841

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/2479756

Change-Id: Icd916a03d76b6f83ac1b26d3f7a58b6cf2359028
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>