ContactPairView::colliderX return Option (#653)

* `ContactPairView::collider1` and `ContactPairView::collider2` now return an `Option`.

* update changelog

Author: ThierryBerger

CHANGELOG.md

@@ -13,6 +13,7 @@
 - Update from rapier `0.23` to rapier `0.24`,
   see [rapier's changelog](https://github.com/dimforge/rapier/blob/master/CHANGELOG.md).
 - `RapierContextInitialization::InitializeDefaultRapierContext` now has more fields for better control over default physics context.
+- `ContactPairView::collider1` and `ContactPairView::collider2` now return an `Option`.
 
 ## Fixed
 

src/plugin/narrow_phase.rs

@@ -347,17 +347,13 @@ pub struct ContactPairView<'a> {
 
 impl ContactPairView<'_> {
     /// The first collider involved in this contact pair.
-    pub fn collider1(&self) -> Entity {
-        self.context_colliders
-            .collider_entity(self.raw.collider1)
-            .unwrap()
+    pub fn collider1(&self) -> Option<Entity> {
+        self.context_colliders.collider_entity(self.raw.collider1)
     }
 
     /// The second collider involved in this contact pair.
-    pub fn collider2(&self) -> Entity {
-        self.context_colliders
-            .collider_entity(self.raw.collider2)
-            .unwrap()
+    pub fn collider2(&self) -> Option<Entity> {
+        self.context_colliders.collider_entity(self.raw.collider2)
     }
 
     /// The number of contact manifolds detected for this contact pair.