Multiple identities: do not reboot immediatelly

[szszszsz]

Do not reboot immediately after setting the identity, but first respond to the hosts query, and then do so.

[szszszsz]

Quick update: it would be nice to send response, otherwise client tools have to ignore the transaction error. Tracking current implementations:

• https://gitlab.com/hkos/openpgp-card/ (NotTransacted error)
• https://github.com/Nitrokey/pynitrokey/blob/762427abe5d9e5ff445e390b907f4bb7d2b8ebe3/pynitrokey/cli/start.py#L69