Merge "Add method to get all valid prefixes in PrefixDelegation class." into main am: f1feca062f am: 982838482e

Original change: https://android-review.googlesource.com/c/platform/packages/modules/NetworkStack/+/2786161

Change-Id: If048f9c6b89313468881f2a54b3791863ef94b59
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>