LibWeb: Let LineBuilder decide on Y-coordinate for float insertion

Instead of reaching into the IFC of the LineBuilder from the BFC, we
should let LineBuilder determine how to deal with the running vertical
float clearance. No functional changes.

Libraries/LibWeb/Layout/LineBuilder.cpp

@@ -162,7 +162,7 @@ CSSPixels LineBuilder::y_for_float_to_be_inserted_here(Box const& box)
         candidate_block_offset = highest_intersection_bottom.value();
     }
 
-    return candidate_block_offset;
+    return max(candidate_block_offset, m_context.vertical_float_clearance());
 }
 
 bool LineBuilder::should_break(CSSPixels next_item_width)