fix QueryIter::sort_unstable_by (#16565)

# Objective

`QueryIter::sort_unstable_by` is mistakenly using `slice::sort_by`.

## Solution

Use `slice::sort_unstable_by`.

Author: Victoronz

crates/bevy_ecs/src/query/iter.rs

@@ -774,7 +774,7 @@ impl<'w, 's, D: QueryData, F: QueryFilter> QueryIter<'w, 's, D, F> {
             )
         };
         let mut keyed_query: Vec<_> = query_lens.collect();
-        keyed_query.sort_by(|(key_1, _), (key_2, _)| compare(key_1, key_2));
+        keyed_query.sort_unstable_by(|(key_1, _), (key_2, _)| compare(key_1, key_2));
         let entity_iter = keyed_query.into_iter().map(|(.., entity)| entity);
         // SAFETY:
         // `self.world` has permission to access the required components.