test(sessds): unskip testcase related to QoS2 handling

apps/emqx/test/emqx_persistent_session_SUITE.erl

@@ -390,9 +390,6 @@ t_connect_session_expiry_interval(Config) ->
     ok = emqtt:disconnect(Client2).
 
 %% [MQTT-3.1.2-23]
-%% TODO: un-skip after QoS 2 support is implemented in DS.
-t_connect_session_expiry_interval_qos2(init, Config) -> skip_ds_tc(Config);
-t_connect_session_expiry_interval_qos2('end', _Config) -> ok.
 t_connect_session_expiry_interval_qos2(Config) ->
     ConnFun = ?config(conn_fun, Config),
     Topic = ?config(topic, Config),