`lightning-hsmtool` does not show mnemonic after typing password

[enaples]

Concerning #8837

Step to reproduce the issue

1. lightning-hsmtool generatehsm /path/to/my/hsm_secret
   a. type abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about
   b. type abandon as password
2. lightning-hsm getsecret /path/to/my/hsm_secret
   a. type abandon as password

Expected result

Shows 12 words mnemonic

Actual behavior

Shows lightning-hsmtool: hsm_secret with passphrase