🐛 Fixup SA lookups

[mjudeikis]

Summary

Service account lookups in claims code is done like this:

serviceAccount, err := v.getter.Cluster(clusterName).GetServiceAccount(namespace, saref.Name)
	if err != nil {
		klog.V(4).Infof("Could not retrieve service account %s/%s: %v", namespace, saref.Name, err)
		return nil, err
	}

this means if we are evaluating service accounts from different shards, we will not be able to do this. This particular client should be the front proxy loopback client, where we gonna route it to the right shard for lookup. Now it's set to roots hard, so it works only when SA lands into the root shard.

Related issue(s)

Fixes #

Release Notes

NONE

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[mjudeikis]

/test all