Correct the namespace of DeviceConfig in VpnTest am: d64b2b1bdd

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2629811

Change-Id: Id6ff27c883e5b913043d3e0fcb17d2249fe69fb3
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>