List virtual-account approvals

Every virtual account this customer can be issued — currency, country, backing bank, and its maintenance fee where one applies — with the review status of each. Only entries with status approved can be opened today. Narrowed to the currencies your organization is approved for. Where a currency has its own virtual-account review, an entry per bank reports where that review stands at the bank; not_started there means an approval that covers other banks, and is resolved by that review rather than by POST /v0/customers/{id}/kyc/sync-approvals. Otherwise not_started means the customer has never been verified for the account type; if they were onboarded before it became available, sync-approvals starts the missing verification. Where the account has its own review, a create at a bank whose entry is not approved is refused with VirtualAccountNotApproved; elsewhere such a bank is VirtualAccountBankNotAvailable. Approvals are cached for up to an hour, and a currency's own virtual-account review for 45 seconds to 5 minutes depending on where it stands, so a freshly granted approval can take that long to appear.