MDL-42723: Hide and handle LDAP error when user not in context being checked
MDL-42723: Hide and handle LDAP error when user not in context being checked

MDL-41304 only fixed the case when 'Search subcontext' is enabled. We need to
fix the case when it's not enabled too.

While silencing errors with an @ should be avoided if possible, there's no
other way to prevent the warnings in this case.

dilawar/moodle