Check that allow-discards flag is set by default on LUKS2 devices

[vojtechtrefny]

We'll need to wait for python-blivet-3.12.0-2.fc43 to make it through rawhide build magic for this to work (it should be available in tomorrows compose).

Depends on storaged-project/blivet#1347 and storaged-project/libblockdev#1095

[vojtechtrefny]

The test passes with the latest rawhide ISO Fedora-Everything-netinst-x86_64-Rawhide-20250313.n.0.iso

[rvykydal]

/test-tmt

[rvykydal]

/test-os-variants

[rvykydal]

/test-os-variants
https://github.com/rhinstaller/kickstart-tests/actions/runs/13854869262

We probably want to disable the test on rhel10 and rhel9, similar as in for example 2d0c58d
I think rather in this PR.

[vojtechtrefny]

/test-os-variants
https://github.com/rhinstaller/kickstart-tests/actions/runs/13854869262

We probably want to disable the test on rhel10 and rhel9, similar as in for example 2d0c58d I think rather in this PR.

The fixes will be available in both 9 and 10 so I think we can wait for few more days/weeks for these to be included and then merge this.

[rvykydal]

/test-os-variants

[rvykydal]

Looks good to me, thank you.