Iris - Crash when reading token data for unregistered token data store

FNetTokenStore::UnRegisterDataStore will set the TUniquePtr<FNetTokenDataStore> to null, but it doesn’t resize the TokenDataStores array. If FNetTokenStore::ReadTokenData is later called, it will get the data store from the TokenDataStores array using the token’s type ID, before calling DataStore->ReadTokenData. However, the DataStore pointer will be null in this case, resulting in a crash.

• Initialize a FNetTokenStore, and create and register a FNetTokenDataStore on it.
• Create a FNetToken from this data store, before deleting and unregistering that FNetTokenDataStore.
• After unregistering the data store, attempt to read the token’s data from the token store.
• Observe the instance crashes as it attempts to dereference a nullptr.

See linked EPS case for repro test.