Avoid potential copies of TraceEvent before serialization (#52196)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/52196

# Changelog: [Internal]

Probably been overlooked for quite some time, but shouldn't be a bottleneck.

Reviewed By: motiz88

Differential Revision: D77148271

fbshipit-source-id: e8eb32137086d6c280aab2ec5903be03f96175ad

packages/react-native/ReactCommon/jsinspector-modern/tracing/PerformanceTracer.cpp

@@ -94,7 +94,7 @@ void PerformanceTracer::collectEvents(
   }
 
   auto traceEvents = folly::dynamic::array();
-  for (auto event : buffer_) {
+  for (const auto& event : buffer_) {
     // Emit trace events
     traceEvents.push_back(serializeTraceEvent(event));