LibWeb: Use correct point type in to_top_level_position()

This occurred because 90a211b changed the return type of
`transform_rect_to_viewport()` but 7fc945d didn't take this into
account.

Author: tcl3

Libraries/LibWeb/HTML/Navigable.cpp

@@ -2592,7 +2592,7 @@ CSSPixelPoint Navigable::to_top_level_position(CSSPixelPoint a_position)
             auto const& scroll_state = viewport_paintable.scroll_state_snapshot();
             auto point = paintable_box->absolute_position();
             point.translate_by(position);
-            position = accumulated_visual_context.transform_rect_to_viewport({ point, { 0, 0 } }, scroll_state).location();
+            position = accumulated_visual_context.transform_rect_to_viewport({ point, { 0, 0 } }, scroll_state).location().to_type<CSSPixels>();
         } else {
             position.translate_by(paintable->box_type_agnostic_position());
         }