emulators/dolphin-emu: Fix build with libfmt 10.1.1+
- Add BUILD_DEPENDS to ensure libfmt 10.1+ is used
Obtained from: https://github.com/dolphin-emu/dolphin/commit/63467559b20682a6b9e4ec43c6b43456e1fca111
https://github.com/dolphin-emu/dolphin/commit/b5b28da39d371ff2abbb0855fadc3c748a8a7043