Features list loops in loading forever

Looks like https://github.com/Flagsmith/flagsmith/pull/7283 resurfacing?

This has been observed when the URL has an incorrect environment identifier, e.g.

```
http://app.flagsmith.com/project/1/environment/undefined/features
```

The "undefined" piece in the URL leads the UI to forever try to load stuff from some API endpoint that will never respond with a 200.

Users reported that this has happened by clicking "Features" from the sidebar. (!)

## Acceptance criteria

- [ ] The app redirects to the default environment (e.g. `/project/1/`) when attempting to load features leads to a 404 because of an incorrect environment identifier.