Fixes reporting of dynamic adapter metrics.

The metrics from the dynamic adapter were not previously being reported.
This change allows them to be reported when all other DRM metrics are
reported.

Bug: 64566432

Test: Unit tests, GTS tests, and Play movies.
Change-Id: I916fb028146fdd04b4cf5bbb5c10ecdaffae6c95

libwvdrmengine/cdm/metrics/include/value_metric.h

@@ -86,6 +86,12 @@ class ValueMetric : public MetricSerializable {
   // Get the current value of the metric.
   const T& GetValue() { return value_; }
 
+  // Clears the indicators that the metric or error was set.
+  void Clear() {
+    has_value_ = false;
+    has_error_ = false;
+  }
+
  private:
   std::string metric_name_;
   T value_;