test(core): updating import on helpers to using jest and not playwright (#7384)

Author: jordanl17

packages/sanity/src/core/studio/router/helpers.test.ts

@@ -1,5 +1,4 @@
-import {describe, it} from '@jest/globals'
-import {expect} from '@playwright/experimental-ct-react'
+import {describe, expect, it} from '@jest/globals'
 import {type Tool} from 'sanity'
 import {type RouterState} from 'sanity/router'