reflect rendertarget (#22113)

RenderTarget was a Component that derived Reflect but did not Reflect
Component

as of this merge today:
67633b3

Without this fix, spawning a scene with a camera (such as from a Blender
export) causes a panic:

> scene contains the unregistered component
`bevy_camera::camera::RenderTarget`. consider adding
`#[reflect(Component)]` to your type

Author: ChristopherBiscardi

crates/bevy_camera/src/camera.rs

@@ -811,7 +811,7 @@ impl Default for CameraOutputMode {
 /// The "target" that a [`Camera`] will render to. For example, this could be a `Window`
 /// swapchain or an [`Image`].
 #[derive(Component, Debug, Clone, Reflect, From)]
-#[reflect(Clone)]
+#[reflect(Clone, Component)]
 pub enum RenderTarget {
     /// Window to which the camera's view is rendered.
     Window(WindowRef),