keyType is not sensitive data (just 'rsa', 'ed25519', 'auto', etc.)
and was being incorrectly encrypted, causing SSH connection failures
with the error: 'Cannot parse privateKey: Unsupported OpenSSH
private key type: slh-rsa' because the client received an
encrypted JSON string instead of the key type.
- Remove keyType from ENCRYPTED_FIELDS in ssh_data set
- Remove keyType from ENCRYPTED_FIELDS in ssh_credentials set
Fixes SSH key authentication for metrics and terminal connections.
Tested: Verified metrics collection returns real data (CPU, memory, disk,
uptime) after this fix.
