file transfers are no longer queued if they fail

we should have the normal abort/retry button if a file transfer fails. pretty sure we used to have this.

### Steps to reproduce

* Be on bad connectivity (e.g. network conditioner)
* Try to upload a file
* Kill the connectivity entirely
* Note that the file transfer fails with "failed to upload"
* Look for a "retry unsent messages" button, which used to exist, but no longer exists (but only for file transfers).

### Outcome

#### What did you expect?

File transfers should get queued and retried under bad connectivity, just as normal messages do.

#### What happened instead?

The file is silently discarded and the user has to manually set up the upload again when they think they might have better connectivity.

### Operating system

macOS

### Browser information

Chrome 106

### URL for webapp

https://develop.element.io

### Homeserver

matrix.org

### Will you send logs?

No