Icon-image (and more layers) should support feature-state

[krupupakku]

User Story

I'd like for more properties to support feature-state, like icon-image to be able to simulate a selection, updating image consequently and avoid duplicating layers with just a styling difference.

Would be fantastic build something like:
'icon-image': ['case', ['boolean', ['feature-state', 'selected'], false], 'my-selected-image', 'my-image'],

Benefits

• data driven styling
• less layers needed
• cleaner for user