`getEntryKey` had some logic to remove `children` if it was part of the entry (originally it was intended to fix an issue with parallel slots that were used in place of a page, but wasn't working as intended). However, this breaks pages that are named `children`.
Updating this again to implement what I think was the intended behavior in 4900fa21b0 which is to point to the correct entry when a parallel slot is used in place of a page component.
- x-ref: #52362
Closes NEXT-1514
Fixes#53072
