test(quic_multistreams): attempt to fix flaky tests

https://github.com/emqx/emqx/actions/runs/5122717037/jobs/9214950882#step:8:1757
```
 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
test_server:ts_tc failed on line 1782
Reason: {test_case_failed,Client <0.6075.5> did not die: stacktrace: {current_stacktrace,
                                            [{gen_statem,loop_receive,3,
                                              [{file,"gen_statem.erl"},
                                               {line,1281}]},
                                             {proc_lib,init_p_do_apply,3,
                                              [{file,"proc_lib.erl"},
                                               {line,240}]}]}}
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Testing lib.emqx.emqx_quic_multistreams_SUITE: *** FAILED test case 335 of 364 ***
%%% emqx_quic_multistreams_SUITE ==> shutdown.abort_recv_shutdown.ctrl_stream_shutdown.t_multi_streams_remote_shutdown: FAILED
%%% emqx_quic_multistreams_SUITE ==> {test_case_failed,"Client <0.6075.5> did not die: stacktrace: {current_stacktrace,\n                                            [{gen_statem,loop_receive,3,\n                                              [{file,\"gen_statem.erl\"},\n                                               {line,1281}]},\n                                             {proc_lib,init_p_do_apply,3,\n                                              [{file,\"proc_lib.erl\"},\n                                               {line,240}]}]}"}
```

```
  %%% emqx_quic_multistreams_SUITE ==> mstream.profiles.profile_max_throughput.pub_qos2.sub_qos2.qos.t_multi_streams_unsub: FAILED
  %%% emqx_quic_multistreams_SUITE ==> {{case_clause,
       {ok,#{packet_id => 8,properties => #{},reason_code => 0,
             reason_code_name => success,
             via =>
                 {quic,#Ref<0.686875463.2755788802.201649>,
                     #Ref<0.686875463.2755788804.193527>}}}},
   [{emqx_quic_multistreams_SUITE,t_multi_streams_unsub,1,
        [{file,
             "/home/thales/dev/emqx/emqx/apps/emqx/test/emqx_quic_multistreams_SUITE.erl"},
         {line,1094}]},
    {test_server,ts_tc,3,[{file,"test_server.erl"},{line,1783}]},
    {test_server,run_test_case_eval1,6,[{file,"test_server.erl"},{line,1292}]},
    {test_server,run_test_case_eval,9,[{file,"test_server.erl"},{line,1224}]}]}
```

apps/emqx/test/emqx_quic_multistreams_SUITE.erl

@@ -24,6 +24,7 @@
 -include_lib("common_test/include/ct.hrl").
 -include_lib("quicer/include/quicer.hrl").
 -include_lib("emqx/include/emqx_mqtt.hrl").
+-include_lib("snabbkaffe/include/snabbkaffe.hrl").
 
 suite() ->
     [{timetrap, {seconds, 30}}].
@@ -1089,6 +1090,11 @@ t_multi_streams_unsub(Config) ->
     ),
 
     emqtt:unsubscribe_via(C, SubVia, Topic),
+    ?retry(
+        _Sleep2 = 100,
+        _Attempts2 = 50,
+        false = emqx_router:has_routes(Topic)
+    ),
 
     case emqtt:publish_via(C, PubVia, Topic, #{}, <<6, 7, 8, 9>>, [{qos, PubQos}]) of
         ok when PubQos == 0 ->
@@ -1569,7 +1575,7 @@ t_multi_streams_remote_shutdown(Config) ->
 
     ok = stop_emqx(),
     %% Client should be closed
-    assert_client_die(C, 100, 50).
+    assert_client_die(C, 100, 200).
 
 t_multi_streams_remote_shutdown_with_reconnect(Config) ->
     erlang:process_flag(trap_exit, true),