Add vendor_socket_hook_prop to whitelist

It's added in system's property_contexts, so it must be listed in
the whitelist.

Bug: 157274431
Test: vts_treble_sys_prop_test
Change-Id: Ia68f737e81e674d0fb4b80d7f31620a9f8df890f
Merged-In: Ia68f737e81e674d0fb4b80d7f31620a9f8df890f
(cherry picked from commit 75a3c478250b185d693b2dfd12e22f25596dffa5)
2 files changed