[Turnbase RPG] Avoid empty errror message key

gistfile1.txt

    public void OnGameServiceError(string error, UnityAction errorAction)
    {
        Debug.LogError("OnGameServiceError: " + error);
        var errorText = string.IsNullOrEmpty(error) || !LanguageManager.Texts.ContainsKey(error) ? "" : LanguageManager.Texts[error];
        messageDialogData.Enqueue(new UIMessageDialog.Data(LanguageManager.Texts[GameText.TITLE_ERROR_DIALOG], errorText, errorAction));
        ShowError();
    }