This function exports the specified wallet account as an encrypted bundle, suitable for backup or transfer.
The exported bundle contains the wallet account’s key material, encrypted to the provided target public key.
If a targetPublicKey is provided, the bundle will be encrypted to that public key; otherwise, an error will be thrown.
If an organizationId is provided, the wallet account will be exported under that sub-organization; otherwise, the current session’s organizationId is used.
Optionally allows stamping the request with a specific stamper (StamperType.Passkey, StamperType.ApiKey, or StamperType.Wallet).