Validate LUKS headers for boots without TPM Disk Unlock Key

[tlaurion]

There was confusion due to the original naming of https://github.com/linuxboot/heads/issues/1092 which #1625 will address when merged.

https://github.com/linuxboot/heads/pull/1625#issuecomment-2025788476

I agree we should validate LUKS headers as well for boots without TPM Disk Unlock Key

This issue is opened to track the issue and plan desired workflow.