main/fribidi: upgrade to 1.0.15
https://github.com/fribidi/fribidi/releases/tag/v1.0.15
Diffing the tarballs, it seems 1.0.14 did not actually use Unicode 15.
https://github.com/fribidi/fribidi/releases/tag/v1.0.15
Diffing the tarballs, it seems 1.0.14 did not actually use Unicode 15.