HPCC-11194 using ~foreign in ecl bypasses ldap security

Currently, if a client ESP does not have LDAP authentication enabled, a
request to check scope permissions on a foreign dali will send an empty
user descriptor. When a foreign dali receives a request with an empty user
descriptor, it injects the global "daliuser" credentials enabling the request
to be granted.
This is incorrect behaviour, since anyone can stand up a cluster with no
LDAP, and then access data on a foreign dali. This fix modifies the client
ESP so that, when sending a request to a foreign dali and there are no
credentials, it injects the "Unauthorized" username into the request, which
will then correctly result in the user being denied access

Signed-off-by: Russ Whitehead <william.whitehead@lexisnexis.com>
Merge remote-tracking branch 'origin/unauth'