By using `Content` instead, now the logic will get the X of the settings
overlay at the `Content` space, which can be scaled in the
`ScalingMode.Everything` mode.
And in the case of `ScalingMode.ExcludeOverlays`, a subcontainer
somewhere inside `Content` that's holding the screen stack would be scaled,
but `Content` won't be affected which is what we want in that case.
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