Disallow `rootParams()` in `cache` scope (#75801)
root params exposes request data and thus must be disallowed from caches
unless the cache also implicitly keys the entries on the root params
values. For now we will simply disallow this pattern. we will implement
a strategy in the future which will allow root params to be called from
inside a cache scope once we can sufficiently key the cache entries by
the root params values read. The same problem will arise with variants
in the future so we will eventually need to implement support
The implementation removes rootParams from the workStore. This is an
invitation to accidentally leak request data into cache scopes. Now
rootParams are conveyed on the workUnitStore and the cache store types
don't define it.
closes NAR-89
