rabbit_mgmt_wm_auth: make sure authSettings/0 is exported

(cherry picked from commit 0bc7884)

Author: michaelklishin

deps/rabbitmq_management/src/rabbit_mgmt_wm_auth.erl

@@ -9,6 +9,7 @@
 
 -export([init/2, to_json/2, content_types_provided/2, is_authorized/2]).
 -export([variances/2]).
+-export([authSettings/0]).
 
 -include_lib("rabbitmq_management_agent/include/rabbit_mgmt_records.hrl").
 -include_lib("rabbit_common/include/rabbit.hrl").