ExternalProject: Stop configure target from always appearing out-of-date

When updates are disconnected, don't depend on skip-update because that
target is always considered out of date. Depend directly on the patch target
instead because it already depends on the appropriate target regardless of
whether updates are disconnected or not. This in turn means nothing depends
on the skip-update target, so it has also been removed.

Relates: #21086
1 file changed