User Story:

With https://issues.redhat.com/browse/AGENT-1302 achieved via https://github.com/openshift/installer/pull/9941, the end goal is not to have a --interactive flag when creating the unconfigured-ignition. The interactive features will always be present in the ignition but disabled by default. Those are only enabled by the presence of sentinel file /etc/assisted/interactive-ui.

This task reverts the changes introduced in appliance for supporting the interactive flow in unconfigured-ignition and add the sentinel file using appliance is invoked as a ISOBuilder vy build --live-iso command