devel/cereal: fix with clang 19 [-Wmissing-template-arg-list-after-template-kw] apply(ar, tuple)

This error manifests during at least the build of math/mlpack on 13.5.
It's only a header file provided from devel/cereal which needs patching.

Approved by: teodor@sigaev.ru
See also: https://github.com/USCiLab/cereal/pull/835
Event: Wiesbaden Hackathon 202604
PR: 285204

(cherry picked from commit e9472d84220320c59c97bf5ed68e0de693559c08)