[neon-notifications] Dev Required: fluidsynth - 2.5.6

[Neon CI]

https://build.neon.kde.org/job/watcher_release_backports-noble_fluidsynth-noble/100/display/redirect

#<Debian::UScan::DEHS::Package:0x00007979a1e51b10 @name="fluidsynth", @debian_uversion="2.5.3+dfsg", @debian_mangled_uversion="2.5.3", @upstream_version="2.5.6", @upstream_url="https://github.com/FluidSynth/fluidsynth/archive/refs/tags/v2.5.6.tar.gz", @status="Newer version available">