Enable deleting user data from persistent caches

This means exposing a function that takes an AuthenticationRecord and ultimately calls an MSAL public client method to remove the specified account. Depending on its implementation details, the SDK function may also need to take an optional cache name. (For example, if it's implemented as a method on a class whose constructor takes a cache name, the function itself doesn't need an argument for that.)

Note that this function would delete data for specific individual accounts and not an entire cache. Deleting an entire cache could unexpectedly log out users of other applications. Deleting only individual accounts shouldn't block any application-level "log out" scenario because Azure.Identity provides an AuthenticationRecord for each user it authenticates.