Passing clean-css options doesn't work

We recently updated all the packages and dependencies in our Ember.js project to their latest versions. Since then when this project is built with the `--environment production` flag, the CSS looks broken when browsing through its web pages. Disabling the CSS minifying fixes the issue.

I am trying to investigate and find out which CSS optimization is breaking our CSS styles, but it doesn't look like passing custom `clean-css` options is working correctly:

`enabled` works:
```
minifyCSS: {
enabled: true // or false
}
```

`level (integer)` works:
```
minifyCSS: {
options: {
level: 1 // 0, 1 or 2
}
}
```

`level (with options)` doesn't work:
```
minifyCSS: {
options: {
level: {
1: {
all: false,
optimizeFont: true
},
2: {
all: false
}
}
}
}
```

Passing the last `options` above does not have the desired result, which would be to only have `optimizeFont` enabled and all other optimizations disabled. The final CSS minifying looks the same as if everything was enabled.

The `clean-css` documentation says that we should be able to individually enable or disable each optimization (https://github.com/clean-css/clean-css?tab=readme-ov-file#level-0-optimizations) but I haven't encountered a single example of such a thing being done in Ember.js or in `ember-cli-clean-css`.