Merge " Improve AllowedNetworkTypesReason and refactor PreferredNetworkType" am: 8c26f14514

Original change: https://android-review.googlesource.com/c/platform/packages/services/Telephony/+/1615179

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I0b21a487215f7c62c3fa70a3748b214758dc40a3