Lars Kiesow a8162b57ba Respond with bad request to unvalid request data
This patch updates the batch progress update endpoint to respond with a
`400 Bad Request` instead of a `500 Internal Server Error` if a user
sends an invalid request with no body. This is a user error after all.

```
❯ curl -i -X PATCH \
  'http://127.0.0.1:3333/api/me/progress/batch/update' \
  -H 'Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5Q_MoRptP0oI' \
  -H 'Content-Type: application/json'
HTTP/1.1 400 Bad Request
…

Missing request payload
```
2022-11-23 02:15:36 +01:00
..
2022-11-09 16:50:26 -06:00
2022-07-06 19:18:27 -05:00