devel/kyua: Deprecate in favor of the base version

• Kyua is part of the base in all supported versions
• Kyua's evolution happens in the base, let's avoid duplicating work
• Set EXPIRATION_DATE to 2026-04-30 (expected 13 branch EOL)

Reviewed by: bofh
Approved by: bofh
Differential Revision: https://reviews.freebsd.org/D47473