net/keycloak: Remove bash as runtime dependency

Keycloak no longer requires bash see:
https://github.com/keycloak/keycloak/pull/21124

PR: 281108
Approved by: Matthias Wolf <freebsd@rheinwolf.de> (maintainer)

(cherry picked from commit 5851a3258eaa98661aaccb0736b00cd4044158eb)