Handle nil name in Gitlab::Auth::LDAP::Person#name

Signed-off-by: NRémy Coutable <remy@rymai.me>

lib/gitlab/auth/ldap/person.rb

@@ -69,7 +69,7 @@ module Gitlab
         end
 
         def name
-          attribute_value(:name).first
+          attribute_value(:name)&.first
         end
 
         def uid