Queued message is sent instead of steering message when steering with a queued message

## Summary
When a message is already queued and the user sends a steering message, the app sends the queued message instead of the steering message.

## Steps to reproduce
1. Queue a message in a session.
2. Before the queued message is sent/processed, send a steering message.
3. Observe which message is delivered to the agent.

## Expected behavior
The steering message should be sent when the user steers, even if another message is queued.

## Actual behavior
The previously queued message is sent instead of the steering message.

## Impact
Users attempting to steer an in-progress or queued interaction may accidentally send stale queued input, making it difficult to correct or redirect the agent.

首先复现所描述的交互：将一条消息加入队列，然后在队列中的消息被处理之前发送一条引导消息。跟踪消息传递流程，以确定为什么会选择队列中的输入。完成的标准是引导消息被传递，并且队列中的消息不会取而代之地被发送。

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