guard against bad upsert op

indexedDb/impl/channels/implementation.go

@@ -414,8 +414,9 @@ func (w *wasmModel) upsertMessage(msg *Message) (uint64, error) {
 
 	// Store message to database
 	msgIdObj, err := impl.Put(w.db, messageStoreName, messageObj)
-	if err != nil {
-		return 0, errors.Errorf("Unable to put Message: %+v", err)
+	if err != nil || msgIdObj.Equal(js.Undefined()) {
+		return 0, errors.Errorf("Unable to put Message: %+v\n%s",
+			err, newMessageJson)
 	}
 
 	uuid := msgIdObj.Int()