Fix non-chat empty messages

Only refuse to send empty message data to the server if it is chat
data.  All other data types can be sent with an empty message (eg,
ping).

wasm/main.go

@@ -224,7 +224,7 @@ func recieve(v []js.Value) {
 }
 
 func websocketSend(msg string, dataType common.ClientDataType) error {
-	if strings.TrimSpace(msg) == "" {
+	if strings.TrimSpace(msg) == "" && dataType == common.CdMessage {
 		return nil
 	}