bootstrap: Heimdal no longer requires perl-JSON

bootstrap: Heimdal no longer requires perl-JSON

Heimdal after lorikeet-heimdal-202307040259
(commit 33d117b8a9c11714ef709e63a005d87e34b9bfde)
includes Heimdal master commit f62e2f278437ff6c03d2d09bd628381c795bba78.

This has PR https://github.com/heimdal/heimdal/pull/1176 and no
longer requires the external JSON module, as JSON::PP is builtin.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15394

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Joseph Sutton <josephsutton@catalyst.net.nz>