refactor: stops using A() with PromiseManyArray

- as it is no longer allowed on Ember 5

addon/utils/utils.js

@@ -3,7 +3,6 @@ import ObjectProxy from '@ember/object/proxy';
 import { isHTMLSafe } from '@ember/template';
 import EmberObject from '@ember/object';
 import { typeOf } from '@ember/utils';
-import { A as emberArray, isArray } from '@ember/array';
 import require from 'require';
 
 function requireModule(module, exportName = 'default') {
@@ -50,7 +49,6 @@ export function isDSManyArray(o) {
   return !!(
     DS &&
     o &&
-    isArray(o) &&
     (o instanceof DS.PromiseManyArray || o instanceof DS.ManyArray)
   );
 }
@@ -75,7 +73,7 @@ export function getValidatableValue(value) {
 
   if (isDSManyArray(value)) {
     value.content = value.content.filter((v) => isValidatable(v));
-    return emberArray(value);
+    return value;
   }
 
   return isValidatable(value) ? value : undefined;