Add any_component_removed condition (#8326)

Added helper extracted from #7711. that PR contains some controversy
conditions, but this one should be good to go.

---

## Changelog

### Added

- `any_component_removed` condition.

---------

Co-authored-by: François <mockersf@gmail.com>

crates/bevy_ecs/src/schedule/condition.rs

@@ -143,6 +143,7 @@ pub mod common_conditions {
  change_detection::DetectChanges,
  event::{Event, EventReader},
  prelude::{Component, Query, With},
+ removal_detection::RemovedComponents,
  schedule::{State, States},
  system::{IntoSystem, Res, Resource, System},
  };
@@ -893,6 +894,17 @@ pub mod common_conditions {
  move |query: Query<(), With<T>>| !query.is_empty()
  }
 
+ /// Generates a [`Condition`](super::Condition)-satisfying closure that returns `true`
+ /// if there are any entity with a component of the given type removed.
+ pub fn any_component_removed<T: Component>() -> impl FnMut(RemovedComponents<T>) -> bool {
+ // `RemovedComponents` based on events and therefore events need to be consumed,
+ // so that there are no false positives on subsequent calls of the run condition.
+ // Simply checking `is_empty` would not be enough.
+ // PERF: note that `count` is efficient (not actually looping/iterating),
+ // due to Bevy having a specialized implementation for events.
+ move |mut removals: RemovedComponents<T>| !removals.iter().count() != 0
+ }
+
  /// Generates a [`Condition`](super::Condition) that inverses the result of passed one.
  ///
  /// # Example