Editing messages which haven't yet remote-echoed now fail without reason.

### Steps to reproduce

1. Send a message on bad connectivity
2. Immediately edit a typo, before it's sent
3. Discover that the edit promptly fails with a red "unable to send message"
4. Hitting retry achieves nothing
5. Looking at the console, it's failing with an error like "cannot send edit to an event without ID"

### Outcome

#### What did you expect?

Edits should be queued until the remote echo has arrived so they can be formed correctly (as I believe used to happen).

Failing that, hitting retry should reform them rather than get stuck sending a malformed message.

Failing that, we should actually surface the error to the user rather than refuse point blank to send the edit for no apparent reason.

#### What happened instead?

Refused to send an edit for undisclosed reasons, feeling unreliable and crap.

### Operating system

_No response_

### Application version

nightly

### How did you install the app?

_No response_

### Homeserver

_No response_

### Will you send logs?

No