Before, we completely ignored clearance for block-level boxes if they
were floated. This was incorrect because it is valid for a block-level
box to be floated and still have clearance. However, unlike clearance
on normal flow boxes, clearance on floating boxes does not affect the
y-position of subsequent normal flow boxes. Instead, it pushes the
box's position to the very beginning of an edge.
Work towards https://github.com/SerenityOS/serenity/issues/21023
