FIX: Analyst installation when booting from ISO should not expect X-Windows to be available

[jertel]

If you boot from the ISO but do not select the analyst workstation install, then when setup runs if you choose Analyst there it will see that you booted from the ISO and assume you did select the analyst workstation kickstart option. One option is to have setup check if X-Windows is installed, and if not, do not allow that setup option. Alternative solutions can be considered but airgap can bring complications.