Remove superfluosus settings-level-expert class

[yubiuser]

What does this PR aim to accomplish?:

Removes settings-level-expert classes where we don't need them. In settings-system they are removed because a parent element is hidden already due to settings-level-expert. In settings-all it's removed because this page can only be accessed in expert mode - no need to hide individual elements.

This ports suggestions from #3487

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[XhmikosR]

Can you try a direct link to advanced page in a new tab after disabling expert settings in your branch? Does it still redirect you?

[yubiuser]

Yes it does.