fix: handle hitsounds with filenames differently

<https://github.com/ppy/osu/blob/b94d3d7a642d53afbedb9d485bb240fc8c3ee1b2/osu.Game/Rulesets/Objects/Legacy/ConvertHitObjectParser.cs#L519-L546>

src/model/beatmap/decode.rs

@@ -614,7 +614,9 @@ impl DecodeBeatmap for Beatmap {
             // filename
             match split.next() {
                 None | Some("") => {}
-                Some(_) => sound = HitSoundType::default(),
+                // Relevant maps:
+                //   - /b/244784 at 43374
+                Some(_) => sound &= !HitSoundType::NORMAL,
             }
 
             Ok(())