Mute notes in locked NBS layers

Author: RaphiMC

src/main/java/net/raphimc/noteblocklib/format/nbs/NbsIo.java

@@ -172,6 +172,10 @@ public static NbsSong readSong(final InputStream is, final String fileName) thro
                         }
                     }
 
+                    if (layer.isLocked()) { // Locked layers are muted
+                        note.setVolume(0F);
+                    }
+
                     song.getNotes().add(noteEntry.getKey(), note);
                 }
             }