Fix a bug in VUR VTS test.

The logic is to check whether each element is not the same as
previous element. We forgot to increase i.

Test: Presubmit
Bug: 326987403
Change-Id: I5cab61a86092fb14d17551a533e8cdaff1abfee5
diff --git a/automotive/vehicle/vts/src/VtsHalAutomotiveVehicle_TargetTest.cpp b/automotive/vehicle/vts/src/VtsHalAutomotiveVehicle_TargetTest.cpp
index ccc0f3f..4ea6dfe 100644
--- a/automotive/vehicle/vts/src/VtsHalAutomotiveVehicle_TargetTest.cpp
+++ b/automotive/vehicle/vts/src/VtsHalAutomotiveVehicle_TargetTest.cpp
@@ -640,13 +640,12 @@
     size_t i = 0;
     float previousValue;
     for (const auto& [_, value] : valuesByTimestamp) {
-        if (i == 0) {
-            previousValue = value;
-        } else {
+        if (i != 0) {
             ASSERT_FALSE(value != previousValue) << "received duplicate value: " << value
                                                  << " when variable update rate is true";
-            previousValue = value;
         }
+        previousValue = value;
+        i++;
     }
 }