fixing another cycle

Author: ef4

packages/@ember/-internals/metal/lib/array.ts

@@ -12,13 +12,7 @@ interface ObservedObject {
   _revalidate?: () => void;
 }
 
-export function objectAt<T>(array: T[] | EmberArray<T>, index: number): T | undefined {
-  if (Array.isArray(array)) {
-    return array[index];
-  } else {
-    return array.objectAt(index);
-  }
-}
+export { objectAt } from './object-at';
 
 // Ideally, we'd use MutableArray.detect but for unknown reasons this causes
 // the node tests to fail strangely.

packages/@ember/-internals/metal/lib/chain-tags.ts

@@ -10,7 +10,7 @@ import {
   updateTag,
   validateTag,
 } from '@glimmer/validator';
-import { objectAt } from './array';
+import { objectAt } from './object-at';
 import { tagForProperty } from './tags';
 
 export const CHAIN_PASS_THROUGH = new WeakSet();

packages/@ember/-internals/metal/lib/object-at.ts

@@ -0,0 +1,9 @@
+import type EmberArray from '@ember/array';
+
+export function objectAt<T>(array: T[] | EmberArray<T>, index: number): T | undefined {
+  if (Array.isArray(array)) {
+    return array[index];
+  } else {
+    return array.objectAt(index);
+  }
+}