Use longer timeout to run sign_virt_apex in tests am: 9bfb1a1126

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Virtualization/+/2067231

Change-Id: I7ce871c6e57cc90255a84472dba2ef47ace7f9c5
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>