[F] [maidata] maidata返回的levels中，现在会忽略内容为空串的谱面

Author: Starrah

collection/Maidata.cs

@@ -88,6 +88,7 @@ private void _putKey(string? key, StringBuilder content)
             if (k.StartsWith("inote_"))
             {
                 if (!int.TryParse(k.Replace("inote_", ""), out var id)) continue;
+                if (string.IsNullOrWhiteSpace(this[k])) continue;
                 // 一边从info中移除内容，一边加到levels里去
                 infos.Remove(k, out var v);
                 infos.Remove($"lv_{id}", out var level);