Description of problem:
In 6.15 we've removed LCE field from Register Host page in WebUI, and added validation when user tries to register with any LCE other than selected CV, for example, non-library LCE with Default Org CV, which won't work.

Version-Release number of selected component (if applicable):
Satellite 6.15.0 Snap 1.0

How reproducible:
Always

Steps to Reproduce:
1. # hammer host-registration generate-command --help | grep lifecycle
--lifecycle-environment[-id] VALUE/NUMBER Lifecycle environment for the host.

Actual results:
LCE option is still present in Hammer/API, and user will get validation errors when registered with command generated above

Expected results:
LCE option not present in Hammer/API

Additional info:
RE: https://github.com/Katello/katello/pull/10764#issuecomment-1846090408