MediaMetrics: Avoid creating temporary string am: 9620663ed8

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/av/+/16358181

Change-Id: I459150a935435d5a043c081b7d3429ddc3410490
diff --git a/media/libmediametrics/MediaMetricsItem.cpp b/media/libmediametrics/MediaMetricsItem.cpp
index 1c71f5c..a7ec975 100644
--- a/media/libmediametrics/MediaMetricsItem.cpp
+++ b/media/libmediametrics/MediaMetricsItem.cpp
@@ -70,7 +70,7 @@
 
 status_t errorStringToStatus(const char *error) {
     const auto& map = getErrorStringMap();
-    if (error == nullptr || error == "") return NO_ERROR;
+    if (error == nullptr || error[0] == '\0') return NO_ERROR;
     auto it = map.find(error);
     if (it != map.end()) {
         return it->second;