[Enhancement] Make att. level 3 button opacity-based

[RasmusKjeldgaard]

• I have written a good issue

Describe the enhancement

The attention level 3 button should be changed from an outline to a see-through layer.

Describe the solution you'd like

Attention level 3 of the button should be implemented with themeColor specific variants for light, white and dark backgrounds. This means they will automatically adapt when placed inside cards.

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[dennispedersen-bd]

Remember to adjust hover and pressed state acording to guidelines

[RasmusKjeldgaard]

New spec: