fix(viewport): preserve hidden-border content

Keep layout viewport content active when its boundary layer is off.

Refs #844

src/scene/paper.rs

@@ -168,7 +168,6 @@ impl Scene {
             if !vp.status.is_on
                 || vp.common.invisible
                 || self.entity_temporarily_hidden(handle)
-                || self.layer_hidden(&vp.common.layer)
             {
                 continue;
             }