message: fix: Fix null object exception with tags
  Fixes
diff: @@ -241,7 +241,8 @@ public class RNSentryModule extends ReactContextBaseJavaModule {
  if (castEvent.hasKey("tags")) {
  for (Map.Entry<String, Object> entry : castEvent.getMap("tags").toHashMap().entrySet()) {
  - eventBuilder.withTag(entry.getKey(), entry.getValue().toString());
  + String tagValue = entry.getValue() != null ? entry.getValue().toString() : "INVALID_TAG";
  + eventBuilder.withTag(entry.getKey(), tagValue);
  }
  }
  