Fix ubsan errors in OPENSSL_sk_pop_free

Fix ubsan errors in OPENSSL_sk_pop_free

ubsan reports an error in the free callback function for
OPENSSL_sk_pop_free.

Need to add a thunking shim to cast the pointer data types to their
proper types

Fixes #29616

Reviewed-by: Saša Nedvědický <sashan@openssl.org>
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Norbert Pocs <norbertp@openssl.org>
MergeDate: Tue Jan 27 17:25:34 2026
(Merged from https://github.com/openssl/openssl/pull/29690)