graphics/wxsvg: Update to 1.5.25
- Fix build with FFmpeg >= 7
ChangeLog: https://sourceforge.net/projects/wxsvg/files/wxsvg/1.5.25/
PR: 289062
Approved by: portmgr (build fix blanket)
MFH: 2025Q3 (bugfix release)
(cherry picked from commit e3c5ee46c5f6dbc3f8de88caee6644bedf78135c)