[DO NOT MERGE] passpoint: validate decorated identity prefix am: 68abe8f273

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/modules/Wifi/+/20035262

Change-Id: I43cc4ec4559831a9ca5638d9f90cfa6008917b71
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>