Large canvas not downsized properly when running wasm build in mobile on itch.io

I'm having trouble with the canvas overflowing when using this template targeting mobile devices and publishing on itch.io.

I'm quite sure the change in this PR https://github.com/bevyengine/bevy_github_ci_template/pull/44 previously fixed the issue and properly resized the canvas to fit smaller screens, by adding the css

```

html, body {margin:0;height:100%;}

```

and configuring the window plugin to use `fit_canvas_to_parent: true`.

But something has changed 🤔 and this does not seem to help anymore as a canvas/window with dimensions larger then the target device will overflow and only show a cropped center part of the canvas/window content, when running on mobile on itch.io.

Anyone having the same issue (with itch.io in particular) and have found a workaround / fix?

Inizia riproducendo la build WASM pubblicata su un dispositivo mobile tramite itch.io, quindi confronta il comportamento del canvas con la configurazione della PR 44. Controlla prima le impostazioni mostrate di CSS e window plugin; il lavoro è completato quando il canvas si adatta al dispositivo di destinazione senza overflow né contenuti tagliati.

Scritto dal modello di indicizzazione a partire dal testo della issue.