fn make_upgrade_token_if_needed(
current_user_key_id: SymmetricKeySlotId,
new_user_key_id: SymmetricKeySlotId,
creates_v2_upgrade_token: bool,
ctx: &mut KeyStoreContext<'_, KeySlotIds>,
) -> Result<Option<Box<V2UpgradeTokenRequestModel>>, ReencryptError>