`isKnownError` import moved under `/errors`

The isKnownError import path has changed from @clerk/nextjs to @clerk/nextjs/errors. You must update your import path in order for it to work correctly. Example below of the fix that needs to be made:

- import { isKnownError } from "@clerk/nextjs"
+ import { isKnownError } from "@clerk/nextjs/errors"