Revert "Fix get_module_opt call in mod_block_strangers"

This reverts commit e5f64bc24a.

src/mod_block_strangers.erl

@@ -59,10 +59,7 @@ filter_packet({#message{} = Msg, State} = Acc) ->
     LBFrom = jid:remove_resource(LFrom),
     #{pres_a := PresA, jid := JID, lserver := LServer} = State,
     AllowLocalUsers =
-        gen_mod:get_module_opt(
-          LServer, ?MODULE, allow_local_users,
-          fun(B) when is_boolean(B) -> B end,
-          true),
+        gen_mod:get_module_opt(LServer, ?MODULE, allow_local_users, true),
     case (Msg#message.body == [] andalso
           Msg#message.subject == [])
         orelse (AllowLocalUsers andalso