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
diff --git a/system_property/VtsTrebleSysPropTest.py b/system_property/VtsTrebleSysPropTest.py
index 6480488..c998c42 100644
--- a/system_property/VtsTrebleSysPropTest.py
+++ b/system_property/VtsTrebleSysPropTest.py
@@ -96,7 +96,8 @@
 
     _SYSTEM_WHITELISTED_TYPES = [
             "vendor_default_prop",
-            "vendor_security_patch_level_prop"
+            "vendor_security_patch_level_prop",
+            "vendor_socket_hook_prop"
     ]
 
     _VENDOR_OR_ODM_WHITELISTED_TYPES = [
diff --git a/system_property/vts_treble_sys_prop_test.py b/system_property/vts_treble_sys_prop_test.py
index 6e27abe..5b15b66 100644
--- a/system_property/vts_treble_sys_prop_test.py
+++ b/system_property/vts_treble_sys_prop_test.py
@@ -153,7 +153,8 @@
 
     _SYSTEM_WHITELISTED_TYPES = [
             "vendor_default_prop",
-            "vendor_security_patch_level_prop"
+            "vendor_security_patch_level_prop",
+            "vendor_socket_hook_prop"
     ]
 
     _VENDOR_OR_ODM_WHITELISTED_TYPES = [