Update mint policy allowlist after account code upgrades

Supporting updates to the policy allowlist in `MintPolicyManager` would let accounts add or remove permitted mint policies after deployment, for example using `add_allowed_policy` and `remove_allowed_policy` or `update_allowed_policies` procedures. This could improve flexibility over time, especially for accounts that may want to adopt new policies or deprecate existing ones.

However, since the accounts are not `Upgradable`, updating the allowlist is not meaningful since newly added allowed policies still need to exist in the deployed account code. After the account code upgradability we should consider adding procedures to update the allowed procedure roots.

The relevant discussion is here: https://github.com/0xMiden/protocol/pull/2559#discussion_r2939305063