net/kafka: fix regression in non-Kraft mode after update to 3.3.1

"There's a regression after update to 3.3.1 in non-Kraft mode
The port always creates /var/db/kafka/kraft dir. But it brokes the Kafka environment."

PR: 267309
Approved by: rene
Differential Revision: https://reviews.freebsd.org/D37731