Commit 561dc357c2f5 changed the way we handle components in the prompt,
and accidentally resulted in the kernel-dbg component not being listed
since we now hide all components ending in "-dbg".
Add an exception for kernel-dbg to bring it back.
Fixes: 561dc357c2f5 ("bsdinstall: Use package sets for pkgbase install")
MFC after: 3 seconds