[LDAP] The WebUI Wizard also should not assign empty config IDs

With 689df9a8 the behaviour to assign only
non-empty config IDs was introduced. Only, this was only effective for CLI
and OCS API.

Related to #3270.

The web UI creates now also a full configuration on first load. This fixes
#5094.

Signed-off-by: Arthur Schiwon <blizzz@arthur-schiwon.de>