Add Reflect to OnReplace (#14620)

# Objective

- Fixes #14337 

## Solution

- Add a `cfg_attr` that derives `Refect` for this type. 

## Testing

- I am going to make sure the tests pass on this PR before requesting
review, If more testing is necessary let me know some good action steps
to take.

crates/bevy_ecs/src/world/component_constants.rs

@@ -29,6 +29,7 @@ pub struct OnInsert;
 /// Trigger emitted when a component is replaced on an entity. See [`crate::component::ComponentHooks::on_replace`]
 /// for more information.
 #[derive(Event)]
+#[cfg_attr(feature = "bevy_reflect", derive(Reflect))]
 pub struct OnReplace;
 
 /// Trigger emitted when a component is removed from an entity. See [`crate::component::ComponentHooks::on_remove`]