Intentionally not using `[Values]` as the scale modes can be applied to
the running game instance directly, rather than recreating it all over
again.
The same could be said for the notification overlay but not sure, seems
like something that should be considered at an `OsuGameTestScene` level
instead (whether the same game instance can be reused for further
testing).
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.
Turns out we likely don't want this, as it means the testing user (using
a visual test browser) will not have access to their beatmaps. Can
revisit at a future date if the temporary files are still an issue.