Update SentryEventExtensions.cs

Author: aritchie

src/Sentry/Platforms/Android/Extensions/SentryEventExtensions.cs

@@ -17,6 +17,11 @@ internal static class SentryEventExtensions
 
     public static SentryEvent ToSentryEvent(this JavaSdk.SentryEvent sentryEvent, JavaSdk.SentryOptions javaOptions)
     {
+        if (sentryEvent?.User != null)
+        {
+            // when we cast this serialize this over, this value must be set
+            sentryEvent.User.Name ??= String.Empty;
+        }
         using var stream = new MemoryStream();
         using var streamWriter = new JavaOutputStreamWriter(stream);
         using var jsonWriter = new JavaSdk.JsonObjectWriter(streamWriter, javaOptions.MaxDepth);