[Guitar Pro] Dynamic information repetition in some versions of Guitar Pro

Creating this issue so that it's tracked somewhere. In GP4 and GP5 files, dynamic information is placed on every note, not just the first note, that is displayed.

Steps to reproduce:
-> Open attached file (where the first note is marked as "mf") in Musescore
-> All notes will be marked as mezzo forte

This likely affects some existing tests so fixing this will mean updating a few of those to remove any extraneous markings that exist. This bug does not apply to GPX files.