WS刚连接成功可以进行 对话，超过30sWS断开后，语音上行停止，需要修复

components/platform/src/multimodal/audio_pipeline.c

@@ -298,6 +298,7 @@ typedef struct {
     TaskHandle_t uplink_send_task;
     volatile bool uplink_recording_active;
     volatile bool uplink_task_exit_requested;
+    volatile bool uplink_send_in_flight;
     multimodal_audio_uplink_cb_t uplink_cb;
     void *uplink_cb_ctx;
     bool opus_ready;