Unrequire VisibilityClass from Node (#17918)

# Objective

The UI doesn't use `ViewVisibility` so it doesn't do anything.

## Solution

Remove it.

Author: ickshonpe

crates/bevy_render/src/view/visibility/mod.rs

@@ -129,7 +129,7 @@ impl InheritedVisibility {
 
 /// A bucket into which we group entities for the purposes of visibility.
 ///
-/// Bevy's various rendering subsystems (3D, 2D, UI, etc.) want to be able to
+/// Bevy's various rendering subsystems (3D, 2D, etc.) want to be able to
 /// quickly winnow the set of entities to only those that the subsystem is
 /// tasked with rendering, to avoid spending time examining irrelevant entities.
 /// At the same time, Bevy wants the [`check_visibility`] system to determine

crates/bevy_ui/src/ui_node.rs

@@ -7,7 +7,6 @@ use bevy_reflect::prelude::*;
 use bevy_render::{
     camera::{Camera, RenderTarget},
     view::Visibility,
-    view::VisibilityClass,
 };
 use bevy_sprite::BorderRect;
 use bevy_transform::components::Transform;
@@ -331,7 +330,6 @@ impl From<Vec2> for ScrollPosition {
     ScrollPosition,
     Transform,
     Visibility,
-    VisibilityClass,
     ZIndex
 )]
 #[reflect(Component, Default, PartialEq, Debug, Clone)]