Visualization footer still visible when request to backend has failed

### What went wrong?

This is really not a big issue, but after a failed request for a visualization, the visualization footer with "download" buttons etc. is still visible.

### What did you expect to happen?

It would be better if we only saw the error message here.

### Screenshot

### Where did you find the bug?

- [ ] https://ianalyzer.hum.uu.nl
- [ ] https://peopleandparliament.hum.uu.nl
- [ ] https://peace.sites.uu.nl
- [ ] a server hosted elsewhere (i.e. not by the research software lab)
- [X] a local server

### Version

5.4.0

### Steps to reproduce

Cause a request vor a visualization to fail (e.g., by throwing an error from the backend temporarily), request a visualization and observe.

Reproduce the failed visualization request on a local server, then trace the error handling and visualization footer rendering. Done means the error message remains visible while the footer and its download buttons are hidden after the backend request fails.

Written by the indexing model from the issue text.