Change media.metrics dump format for ALOG()

change a constant from -1 to PROTO_LAST so that we'll include any recent
fields when we debug.

Bug: 72406222
Test: manual, logcat examination
diff --git a/media/libmediametrics/MediaAnalyticsItem.cpp b/media/libmediametrics/MediaAnalyticsItem.cpp
index 423dfb8..2e7efad 100644
--- a/media/libmediametrics/MediaAnalyticsItem.cpp
+++ b/media/libmediametrics/MediaAnalyticsItem.cpp
@@ -722,7 +722,7 @@
 
 
 std::string MediaAnalyticsItem::toString() {
-   return toString(-1);
+   return toString(PROTO_LAST);
 }
 
 std::string MediaAnalyticsItem::toString(int version) {