Increase VHAL property to V4.

Flag: EXEMPT HAL change
Bug: 360461541
Test: Presubmit
Change-Id: I3ff3e65ca19c980d03364da2653553ad477961de
diff --git a/automotive/vehicle/vts/Android.bp b/automotive/vehicle/vts/Android.bp
index 40aec59..433ac41 100644
--- a/automotive/vehicle/vts/Android.bp
+++ b/automotive/vehicle/vts/Android.bp
@@ -43,7 +43,7 @@
         "vhalclient_defaults",
     ],
     header_libs: [
-        "IVehicleGeneratedHeaders-V3",
+        "IVehicleGeneratedHeaders-V4",
     ],
     test_suites: [
         "general-tests",