macosx: Fix font selection when some fonts are disabled
macosx: Fix font selection when some fonts are disabled

Usage of selectedFont inside changeFont: is not allowed, and its
not needed as all the necessary work is done in convertFont:.

close #13740

xkfz007/vlc,krichter722/vlc,vlc-mirror/vlc,krichter722/vlc,shyamalschandra/vlc,xkfz007/vlc,vlc-mirror/vlc,vlc-mirror/vlc,xkfz007/vlc,vlc-mirror/vlc,xkfz007/vlc,xkfz007/vlc,shyamalschandra/vlc,vlc-mirror/vlc,shyamalschandra/vlc,shyamalschandra/vlc,xkfz007/vlc,vlc-mirror/vlc,krichter722/vlc,shyamalschandra/vlc,vlc-mirror/vlc,krichter722/vlc,krichter722/vlc,krichter722/vlc,shyamalschandra/vlc,krichter722/vlc,shyamalschandra/vlc,xkfz007/vlc