Fixes #37461 - Don't use the Kickstart rhsm for RHEL 8

[stejskalleos]

The rhsm command has some issues on RHEL 8,
before it was not enabled for RHEL8 until the PR#9745.

refs bf03a25

[Gauravtalreja1]

ACK, I've tested the PR and it works as expected.
and, now that we are just using kickstart_rhsm for RHEL9 and beyond, shouldn't the PR title/commit message be s/Don't use the Kickstart rhsm for RHEL 9/Don't use the Kickstart rhsm for RHEL 8?

[stejskalleos]

@Gauravtalreja1 Thanks for testing and the sharp eye! Title and commit message changed to RHEL 8

[ekohl]

I recall that RHEL 8 has a completely different implementation of the rhsm command compared to RHEL 9. CI is still running, but feel free to merge it yourself once it's green.