FirePerf: use FPRLogDebug instead of FPRLogError for logging events when FirePerf is disabled (#8620)

* make Dropping Event log use the highest verbosity which is debug

* changelog

Author: leotianlizhan

FirebasePerformance/CHANGELOG.md

@@ -1,5 +1,6 @@
 # Pending
 * Create a random number of delay for remote config fetch during app starts.
+* Fix log spamming when Firebase Performance is disabled. (#8423)
 
 # Version 8.6.1
 * Fix the case where the event were dropped for missing a critical field in the event.

FirebasePerformance/Sources/FPRClient.m

@@ -252,7 +252,7 @@ - (void)logGaugeMetric:(nonnull NSArray *)gaugeData forSessionId:(nonnull NSStri
 - (void)processAndLogEvent:(firebase_perf_v1_PerfMetric)event {
   BOOL tracingEnabled = self.configuration.isDataCollectionEnabled;
   if (!tracingEnabled) {
-    FPRLogError(kFPRClientPerfNotConfigured, @"Dropping event since data collection is disabled.");
+    FPRLogDebug(kFPRClientPerfNotConfigured, @"Dropping event since data collection is disabled.");
     return;
   }