command like message being deleted

### Steps to reproduce

I wrote a long message starting with a slash "/". It wasn't intended as command and at that time I didn't know, that a slash starts a command.

### Outcome

#### What did you expect?
At least the message should be send or stay in the text input field for further editing.
Ideally there should be some help for non-technical users, which don't understand that messages starting with a slash are interpreted as command.
The [desktop client](https://github.com/element-hq/element-desktop) actually asks the user if the _"unknown command"_ was actually meant as message.

#### What happened instead?
Element showed an "unknown command" dialog and deleted the message from the text input field without sending it.
_(a message that was maybe crafted over many minutes shouldn't just be "deleted")_

### Your phone model

Fairphone 3+

### Operating system version

Android 13

### Application version and app store

1.6.24

### Homeserver

matrix.org

### Will you send logs?

No

### Are you willing to provide a PR?

No