[automerger skipped] Unregister after replacement for network agent to avoid...

[automerger skipped] Unregister after replacement for network agent to avoid onLost am: 708aab72 am: 9139e75f am: 40394925 -s ours

am skip reason: Merged-In I816a1b6e3a7ee77b9158ef9ee2331168076ba2c2 with SHA-1 879fae04 is already in history

Original change: https://android-review.googlesource.com/c/platform/frameworks/opt/telephony/+/2470821



Change-Id: If3d558bd003bcf7e1eb7a77944dfabaa844a2d70
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>