Netlify build image out of support - fails on latest image

The netlify build system uses `Ubuntu Focal 20.04` . This falls out of support on Jan 1st 2026.

I tried updating to their new image `Ubuntu Noble 24.04` - but hit errors:

```
2:51:40 PM: Loaded Integrations.
2:51:48 PM: [11ty] Unhandled rejection in promise: (more in DEBUG output)
2:51:48 PM: [11ty] heifsave: Unsupported compression (via Error)
2:51:48 PM: [11ty]
2:51:48 PM: [11ty] Original error stack trace: Error: heifsave: Unsupported compression
2:51:48 PM: [11ty] Unhandled rejection in promise: (more in DEBUG output)
2:51:48 PM: [11ty] heifsave: Unsupported compression (via Error)
```

I have reverted back to the older image for now - it'll still work for the time being. But we will need to update and figure out why it causes the build to fail.