Fix "securedrop-admin verify" kernel checks

[rmol]

Status

Ready for review

Description of Changes

Adds the new kernel version variables to molecule/testinfra/vars/prod*.yml.

Testing

Run securedrop-admin verify against a production Focal installation, on hardware or in VMs. There should be no AttributeError: 'Myvalues' object has no attribute 'grsec_version_focal' errors.

Deployment

Test only. Kinda. It will fix the configuration tests for production instances.

Checklist

If you made non-trivial code changes:

• I have written a test plan and validated it for this PR

Choose one of the following:

• I have opened a PR in the docs repo for these changes, or will do so later
• I would appreciate help with the documentation
• These changes do not require documentation

[conorsch]

Thanks, @rmol. I should have tacked these on during review of #5712. Approving based on visual review, although will need a rebase once we figure out #5799.

[emkll]

Rebased on latest develop to get CI passing. Approving based on prior review and visual diff. Good to merge when CI passes.