v5_SUITE: session_upgrade_v3_v5_qos1

Prior to this commit, the following test case flaked:
```
make -C deps/rabbitmq_mqtt ct-v5 t=cluster_size_1:session_upgrade_v3_v5_qos1
```

The test case failed with:
```
{v5_SUITE,session_upgrade_v3_v5_qos,1112}
{test_case_failed,Received unexpected PUBLISH payload. Expected: <<"2">> Got: <<"1">>}
```

The broker logs showed:
```
2025-07-15 15:50:23.914152+00:00 [debug] <0.758.0> MQTT accepting TCP connection <0.758.0> (127.0.0.1:38594 -> 127.0.0.1:27005)
2025-07-15 15:50:23.914289+00:00 [debug] <0.758.0> Received a CONNECT, client ID: session_upgrade_v3_v5_qos, username: undefined, clean start: false, protocol version: 3, keepalive: 60, property names: []
2025-07-15 15:50:23.914403+00:00 [debug] <0.758.0> MQTT connection 127.0.0.1:38594 -> 127.0.0.1:27005 picked vhost using plugin_configuration_or_default_vhost
2025-07-15 15:50:23.914480+00:00 [debug] <0.758.0> User 'guest' authenticated successfully by backend rabbit_auth_backend_internal
2025-07-15 15:50:23.914641+00:00 [info] <0.758.0> Accepted MQTT connection 127.0.0.1:38594 -> 127.0.0.1:27005 for client ID session_upgrade_v3_v5_qos
2025-07-15 15:50:23.914977+00:00 [debug] <0.758.0> Received a SUBSCRIBE with subscription(s) [{mqtt_subscription,
2025-07-15 15:50:23.914977+00:00 [debug] <0.758.0>                                             <<"session_upgrade_v3_v5_qos">>,
2025-07-15 15:50:23.914977+00:00 [debug] <0.758.0>                                             {mqtt_subscription_opts,1,false,
2025-07-15 15:50:23.914977+00:00 [debug] <0.758.0>                                              false,0,undefined}}]
2025-07-15 15:50:23.924503+00:00 [debug] <0.764.0> MQTT accepting TCP connection <0.764.0> (127.0.0.1:38608 -> 127.0.0.1:27005)
2025-07-15 15:50:23.924922+00:00 [debug] <0.764.0> Received a CONNECT, client ID: session_upgrade_v3_v5_qos, username: undefined, clean start: false, protocol version: 5, keepalive: 60, property names: []
2025-07-15 15:50:23.925589+00:00 [error] <0.758.0> writing to MQTT socket #Port<0.63> failed: closed
2025-07-15 15:50:23.925635+00:00 [debug] <0.764.0> MQTT connection 127.0.0.1:38608 -> 127.0.0.1:27005 picked vhost using plugin_configuration_or_default_vhost
2025-07-15 15:50:23.925670+00:00 [info] <0.758.0> MQTT connection <<"127.0.0.1:38594 -> 127.0.0.1:27005">> will terminate because peer closed TCP connection
2025-07-15 15:50:23.925727+00:00 [debug] <0.764.0> User 'guest' authenticated successfully by backend rabbit_auth_backend_internal
2025-07-15 15:50:24.000790+00:00 [info] <0.764.0> Accepted MQTT connection 127.0.0.1:38608 -> 127.0.0.1:27005 for client ID session_upgrade_v3_v5_qos
2025-07-15 15:50:24.016553+00:00 [warning] <0.764.0> MQTT disconnecting client <<"127.0.0.1:38608 -> 127.0.0.1:27005">> with client ID 'session_upgrade_v3_v5_qos', reason: normal
```

This shows evidence that the MQTT server connection did not process the
DISCONNECT packet. The hypothesis is that the server connection did not
even process the PUBACK packet from the client. Hence, the first message
got requeued and re-delivered to the new v5 client.

This commit fixes this flake by not acking the first message.
Hence, we always expect that the first message will be redelivered to
the new v5 client.

Author: ansd

deps/rabbitmq_mqtt/test/v5_SUITE.erl

@@ -1079,12 +1079,7 @@ session_upgrade_v3_v5_qos(Qos, Config) ->
     {ok, _, [Qos]} = emqtt:subscribe(Subv3, Topic, Qos),
     Sender = spawn_link(?MODULE, send, [self(), Pub, Topic, 0]),
     receive {publish, #{payload := <<"1">>,
-                        client_pid := Subv3,
-                        packet_id := PacketId}} ->
-                case Qos of
-                    0 -> ok;
-                    1 -> emqtt:puback(Subv3, PacketId)
-                end
+                        client_pid := Subv3}} -> ok
     after ?TIMEOUT -> ct:fail("did not receive 1")
     end,
     %% Upgrade session from v3 to v5 while another client is sending messages.
@@ -1108,7 +1103,7 @@ session_upgrade_v3_v5_qos(Qos, Config) ->
         0 ->
             assert_received_no_duplicates();
         1 ->
-            ExpectedPayloads = [integer_to_binary(I) || I <- lists:seq(2, NumSent - 1)],
+            ExpectedPayloads = [integer_to_binary(I) || I <- lists:seq(1, NumSent - 1)],
             ok = expect_publishes(Subv5, Topic, ExpectedPayloads)
     end,
     ok = emqtt:disconnect(Pub),