[bug#74633] [PATCH v2] ui: Search channels for guix extensions

[Brian Kubisiak <brian@kubisiak.com>]

> Could you send a v3 along these lines, if you think that makes sense?

Sent. Note that during testing I noticed that guile-git (and
guile-json-4) needed to be added as dependencies to a g-expression
that imported guix/build/utils.scm due to the additional dependencies
introduced in this patch. I'm probably missing more places where this
is required and Carlo's lazy import may be a better option to avoid
issues like this. Let me know what you think, I can send another
version if you think that's better.

> > +++ b/gnu/packages.scm
> > @@ -148,15 +148,16 @@ (define %package-module-path
> >    (let* ((not-colon   (char-set-complement (char-set #\:)))
> >           (environment (string-tokenize (or (getenv "GUIX_PACKAGE_PATH") "")
> >                                         not-colon))
> > -         (channels-scm channels-go (package-path-entries)))
> > +         (channels-scm (package-path-entries)))
>
> This variable is now unused; I think it can be removed.

This is still used in the below make-parameter call (not shown in the
patch), so I've left it in.

Thanks,
Brian