MXID is added to the text of pill when anti-spoof is triggered

### Steps to reproduce

1. Join two people in a room with the same display name ("val" in the example below)
2. Type `@`
3. Pick one of the two people
4. type "test" (optional) and send

### Outcome

#### What did you expect?

Element-android sends this:

```json
{
"body": "val @val:libera.chat: test",
"format": "org.matrix.custom.html",
"formatted_body": "val @val:libera.chat: test",
"msgtype": "m.text"
}
```

Which causes appservice-irc to send this:

```
17:26:57 val @val:libera.chat: test
```

#### What happened instead?

Element-android should send this:

```json
{
"body": "val @val:libera.chat: test",
"format": "org.matrix.custom.html",
"formatted_body": "val: test",
"msgtype": "m.text"
}
```

Which would cause appservice-irc to send this:

```
17:26:57 val: test
```

### Your phone model

Fairphone 3

### Operating system version

LineageOS 19 (Android 12)

### Application version and app store

1.5.10 from F-Droid

### Homeserver

_No response_

### Will you send logs?

Yes

### Are you willing to provide a PR?

No