fix(audience): drop packageVersion from sample config echo

AudienceConfig.PackageVersion was removed; the sample's diagnostic
config echo no longer compiles against it. libraryVersion is no longer
a config value, so it is dropped from the echo.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: nattb8

examples/audience/Assets/SampleApp/Scripts/AudienceSample.cs

@@ -368,7 +368,6 @@ private static Dictionary<string, object> BuildConfigEcho(AudienceConfig config)
                 ["enableMobileAttribution"]  = config.EnableMobileAttribution,
                 ["flushIntervalSeconds"]     = config.FlushIntervalSeconds,
                 ["flushSize"]                = config.FlushSize,
-                ["packageVersion"]           = config.PackageVersion,
                 ["shutdownFlushTimeoutMs"]   = config.ShutdownFlushTimeoutMs,
             };
             if (!string.IsNullOrEmpty(config.PublishableKey))