Remove toBeArrayOfUniqueItems custom matcher

It is only ever used to assert that an array returned by Object.keys is
unique, and that's always going to be true as an object can't have two
keys with the same name.

packages/react-i18n/src/tests/e2e/server.test.tsx

@@ -2,8 +2,6 @@
  * @jest-environment node
  */
 
-import '../matchers';
-
 import React from 'react';
 import {renderToStaticMarkup} from 'react-dom/server';
 import {extract, Effect} from '@shopify/react-effect/server';
@@ -105,7 +103,6 @@ describe('server', () => {
     const translations = manager.extract();
 
     const extractedTranslations = Object.values(translations);
-    expect(Object.keys(translations)).toBeArrayOfUniqueItems();
     expect(extractedTranslations).toContain(frCATranslations);
     expect(extractedTranslations).toContain(frTranslations);
   });

packages/react-i18n/src/tests/i18n.test.ts

@@ -1,7 +1,5 @@
 import {clock} from '@shopify/jest-dom-mocks';
 
-import './matchers';
-
 import {I18n} from '../i18n';
 import {LanguageDirection} from '../types';
 import {DateStyle, Weekday} from '../constants';

packages/react-i18n/src/tests/manager.test.ts

@@ -1,5 +1,3 @@
-import './matchers';
-
 import {animationFrame} from '@shopify/jest-dom-mocks';
 
 import {I18nManager} from '../manager';
@@ -447,8 +445,6 @@ describe('I18nManager', () => {
       await manager.resolve();
 
       const translationsByID = manager.extract();
-      expect(Object.keys(translationsByID)).toBeArrayOfUniqueItems();
-
       const translations = Object.values(translationsByID);
       expect(translations).toContain(enUS);
       expect(translations).toContain(en);

tests/setup/tests.ts

@@ -1,4 +1,3 @@
-import '../matchers';
 import '../../packages/react-testing/src/matchers';
 import '../../packages/graphql-testing/src/matchers';