fix(agent): 在识别回调前停止当前会话

添加了在调用recognizeCallback之前停止当前会话的逻辑，以避免潜在的冲突

lib/modules/agent/controllers/agent_controller.dart

@@ -1076,6 +1076,8 @@ class AgentController extends GetxController {
     // }
 
     try {
+      await AgentService.stopConversation();
+
       await AgentService.recognizeCallback();
       if (_bluetoothManager.currentDeviceRx.value != null) {
         //  await AgentService.restoreOriginalAudioState();