Fix typo in vts_treble_sys_prop_test am: 7a728bbd90

Original change: https://android-review.googlesource.com/c/platform/test/vts-testcase/security/+/1552038

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Icc5318d3bcafe54495502f2a6a2fc83c95b60118