Use SocketKey in MdnsServiceCache am: 775840e1b4 am: 2fbd1459b7

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2648319

Change-Id: I9d474fa9beec9b816a4d6d45f2b9c85bc77d7ff7
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>