Fix rule engine build fail (#4673)

* fix: add rule engine resources time

apps/emqx_rule_engine/src/emqx_rule_engine_app.erl

@@ -29,6 +29,7 @@ start(_Type, _Args) ->
     _ = emqx_rule_engine_sup:start_locker(),
     ok = emqx_rule_engine:load_providers(),
     ok = emqx_rule_engine:refresh_resources(),
+    timer:sleep(3000),
     ok = emqx_rule_engine:refresh_rules(),
     ok = emqx_rule_engine_cli:load(),
     {ok, Sup}.