[hardware][interfaces][vehicle] fix -Wdangling-gsl in test

Chaining the method calls in such a way otherwise returns a dangling
pointer to a temporary object.

Bug: 139945549
Test: mm
Change-Id: I0783fccbb6f11e7e37bd059445265227359649cf
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
diff --git a/automotive/vehicle/2.0/default/tests/VehicleObjectPool_test.cpp b/automotive/vehicle/2.0/default/tests/VehicleObjectPool_test.cpp
index a291351..4e3ade1 100644
--- a/automotive/vehicle/2.0/default/tests/VehicleObjectPool_test.cpp
+++ b/automotive/vehicle/2.0/default/tests/VehicleObjectPool_test.cpp
@@ -57,11 +57,11 @@
 };
 
 TEST_F(VehicleObjectPoolTest, valuePoolBasicCorrectness) {
-    void* raw = valuePool->obtain(VehiclePropertyType::INT32).get();
+    auto value = valuePool->obtain(VehiclePropertyType::INT32);
     // At this point, v1 should be recycled and the only object in the pool.
-    ASSERT_EQ(raw, valuePool->obtain(VehiclePropertyType::INT32).get());
+    ASSERT_EQ(value.get(), valuePool->obtain(VehiclePropertyType::INT32).get());
     // Obtaining value of another type - should return a new object
-    ASSERT_NE(raw, valuePool->obtain(VehiclePropertyType::FLOAT).get());
+    ASSERT_NE(value.get(), valuePool->obtain(VehiclePropertyType::FLOAT).get());
 
     ASSERT_EQ(3u, stats->Obtained);
     ASSERT_EQ(2u, stats->Created);