feat: ensure that both the account and public key get inserted successfully in the CLI

In #718 we separated the secret key storage from the `Client`. The CLI now has the responsibility of adding new keys to the keystore, but there could be a case where the key is inserted but the new account can be added to the client.

>This is fine for now but maybe we could add a `TODO` here to address potential cases where adding the secret key succeeds, but adding the account fails.
>
>Alternatively, maybe in the future we want to have some sort of "keystore" command that adds/removes keys separately from accounts.

_Originally posted by @igamigo in https://github.com/0xPolygonMiden/miden-client/pull/718#discussion_r1949770347_