SSH key hint text doesn't reflect minimum ECDSA key size requirements

When an instance is configured to require a minimum of 521 bits for ECDSA keys, the "Add new key" dialog displays an incorrect hint that still lists all ECDSA key types.

Current Behavior

The hint below the Key field reads: "Begins with 'ssh-rsa', 'ecdsa-sha2-nistp256', 'ecdsa-sha2-nistp384', or 'ecdsa-sha2-nistp521'."

Expected Behavior

When 521-bit minimum is required, it should exclude the smaller key types and only show: "Begins with 'ssh-rsa' or 'ecdsa-sha2-nistp521'."

Steps to Reproduce

1. Configure instance to require at least 521 bits for ECDSA keys
2. Navigate to User Settings > SSH Keys > Add new key
3. Observe the hint text below the Key field