fix(otel): override sub qos upgrade/downgrade

apps/emqx_opentelemetry/src/emqx_otel_trace.erl

@@ -765,7 +765,9 @@ stop_outgoing_trace(Packet, Attrs) when is_record(Packet, mqtt_packet) ->
     %% Maybe awaiting for next Packet
     %% The current outgoing Packet SHOULD NOT be modified
     ok = outgoing_maybe_awaiting_next(Packet, Attrs),
-    end_span(get_ctx(Packet));
+    Ctx = get_ctx(Packet),
+    ok = add_span_attrs(#{'message.qos' => emqx_packet:qos(Packet)}, Ctx),
+    end_span(Ctx);
 stop_outgoing_trace(Any, _Attrs) ->
     end_span(get_ctx(Any)).