Rageshake sometimes fails with mystery 400 error

### Steps to reproduce

Rageshakes were taking a very long time to upload on roaming data, and eventually failed with a 400.

Part of this was that it was trying to reupload the logs twice: https://github.com/vector-im/element-ios/issues/6595

However, we need to have logging on the response body to see what the 400 actually was.

### Outcome

#### What did you expect?

Rageshakes should work.

### Your phone model

_No response_

### Operating system version

_No response_

### Application version

1.8.25-debug

### Homeserver

matrix.org

### Will you send logs?

Yes