Flow Fuse Dashboard empty for invisible element

### Current Behavior

I've added multiple pages for my dashboard. Because I wanted to build different demos, I wanted to hide some of those, however when doing so, the dashboard disappears entirely, and the page is empty. The browser log shows:
```
Laden des Moduls von "http://172.29.197.122:11880/dashboard/demo2/assets/index-DEHum2uc.js" wurde auf Grund eines nicht freigegebenen MIME-Typs ("text/html") blockiert.
[status](http://172.29.197.122:11880/dashboard/demo2/status)
Laden fehlgeschlagen für das Modul mit der Quelle "http://172.29.197.122:11880/dashboard/demo2/assets/index-DEHum2uc.js". [status:22:72](http://172.29.197.122:11880/dashboard/demo2/status)
Stylesheet http://172.29.197.122:11880/dashboard/demo2/assets/index-VgB8yK84.css wurde nicht geladen, weil sein MIME-Typ, "text/html", nicht "text/css" ist.
```

which is German and translates to something like "could not load module of "[url]" due to blocked MIME-Type ("text/html")" and "could not load stylesheet for [url], because its MIME-Type is "text/html" and not "text/css"".

### Expected Behavior

It should load the dashboard without the page, which it initially does until I do a page refresh.

### Steps To Reproduce

I am not entirely sure if it is completely reproduceable, but this is what I did, basically:
- add 2 pages with content
- make 1 page invisible

### Environment

- Dashboard version: 1.8.1 and 1.9.1
- Node-RED version: v3.1.8
- Node.js version: v18.20.0
- npm version: -
- Platform/OS: Linux 5.15.146.1-microsoft-standard-WSL2 x64 on Windows 11
- Browser: Firefox 125.0.3

### Have you provided an initial effort estimate for this issue?

I am not a FlowFuse team member