textproc/fcitx5: Fix compatibility with fmt 10+

Backport upstream commit 7fb3a5500270877d93b61b11b2a17b9b8f6a506b
to fix build with fmt 10+

Reference:
https://github.com/fcitx/fcitx5/commit/7fb3a5500270877d93b61b11b2a17b9b8f6a506b

PR: 273876
Approved by: portmgr (maintainer timeout, 3+ weeks)
Sponsored by: Blinkinblox