Stuck message due to failure to correlate /send with /sync

### Steps to reproduce

1. Sent message
2. Message was apparently received
3. Didn't get remote echo
4. Therefore msg is stuck at the bottom of the timeline

### Outcome

#### What did you expect?

Never to have stuck messages, especially as it could mean that msgs are going missing from /sync responses.

#### What happened instead?

Stuck msg.

### Operating system

_No response_

### Application version

Element version: 1.12.3 Crypto version: Rust SDK 0.14.0 (c3b7918), Vodozemac 0.9.0

### How did you install the app?

_No response_

### Homeserver

matrix.org

### Will you send logs?

Yes