first try to use the system proxy for all network communication
fix #22978
fix #22978: crash on loading 1.3 scoresw with empty cleflist and ledger lines
fix slur insertion when range selected
fix #22992
fix typo!
fix #22997: Spanners in MusicXML crash MuseScore
fix #23000: Undo does not restore former sizing of stem
fix #22796: disable 'go to next/previous measure' button, if there is no such measure