rabbit_stream_queue_SUITE: Swap uses of node 2 and 3 in format

[Why]
We hit some transient errors with the previous order when doing
mixed-version testing. Swapping the nodes seems to fix the problem.

Author: dumbbell

deps/rabbit/test/rabbit_stream_queue_SUITE.erl

@@ -1565,13 +1565,13 @@ format(Config) ->
     case length(Nodes) of
         3 ->
             [_, Server2, Server3] = Nodes,
-            ok = rabbit_control_helper:command(stop_app, Server2),
             ok = rabbit_control_helper:command(stop_app, Server3),
+            ok = rabbit_control_helper:command(stop_app, Server2),
 
             Fmt2 = rabbit_ct_broker_helpers:rpc(Config, Server, rabbit_stream_queue,
                                                ?FUNCTION_NAME, [QRecord, #{}]),
-            ok = rabbit_control_helper:command(start_app, Server2),
             ok = rabbit_control_helper:command(start_app, Server3),
+            ok = rabbit_control_helper:command(start_app, Server2),
             ?assertEqual(stream, proplists:get_value(type, Fmt2)),
             ?assertEqual(minority, proplists:get_value(state, Fmt2)),
             ?assertEqual(Server, proplists:get_value(leader, Fmt2)),