This allows setting ForceWithoutCrossSigning when reconfiguring the CA
for any provider, in order to forcibly move to a new root in cases where
the old provider isn't reachable or able to cross-sign for whatever
reason.
After fixing that bug I uncovered a couple more:
Fix an issue where we might try to cross sign a cert when we never had a valid root.
Fix a potential issue where reconfiguring the CA could cause either the Vault or AWS PCA CA providers to delete resources that are still required by the new incarnation of the CA.
Kyle Havlovitz