Fixes T10940. Two issues currently:
First, PullLocal deamon refuses to update non-cluster repositories on cluster devices. However, this is surprising/confusing/bad because as soon as you enroll a repository host in the cluster, most of the repositories on it stop working until you clusterize them. This is especially confusing because the documentation gives you a very nice, gradual walkthrough about going through things slowly and being able to check your work at every step, but we really drop you off a bit of a cliff here. The workflow implied by the documentation is a desirable one.
This operation is generally only unsafe/problematic if the daemon would be creating a new working copy. If a working copy already exists, we can reasonably guess that it's almost certainly because you've enrolled a previously un-clustered host into a new cluster. This allows the nice, gradual workflow the documentation describes to proceed as expected, without any weird surprises.
Instead of refusing to update these repositories, only refuse to update them if updating would create a new working copy. This should make transitioning much smoother without any meaningful reduction in safety.
Second, the lower-level bin/repository update, refs, mirror, etc., commands don't apply this same check. However, these commands are potentially just as dangerous. Use the same code to do a similar check there, making sure we only operate on repositories that are either expected to be on the current device, or which already exist here.