audio/fluidsynth: Update to upstream release 2.5.2
Details:
- Bugfix release, see https://github.com/FluidSynth/fluidsynth/releases/tag/v2.5.2
- Includes a fix for CVE-2025-68617 (use after free)
MFH: 2025Q4
Security: CVE-2025-68617
(cherry picked from commit 1276053c82a63a042e022ceff500d1920f04bebe)