Rename metrics.proto to wv_metrics.proto.

Merge from http://go/wvgerrit/105767

To avoid conflict with metrics.proto in
frameworks/av/drm/libmediadrm/proto.
This is in preparation of moving metrics_dump tool
to build under Android.

bug: 161783052
Test: unit test
Test: Play Movies & Tv and Netflix streaming
Change-Id: I2406b66db4d61cca7c6260ea8847a555d96c8d42

libwvdrmengine/cdm/metrics/test/value_metric_unittest.cpp

@@ -9,7 +9,7 @@
 
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
-#include "metrics.pb.h"
+#include "wv_metrics.pb.h"
 
 namespace wvcdm {
 namespace metrics {