ssbc: Fix resolution errors
Created by: eseliger
There are two errors that we didn't catch:
- A search that would not return anything would silently select all user-visible repos (ugh)
- The search can return repos that aren't yet cloned. It doesn't make sense to error out in that case because for some instances that might always be the case (Cloud for example). Instead we treat them as if they didn't exist yet.
Test plan
Added cases for the two edge-cases to our extensive tests and validated manually it doesn't break anything. Experimental feature, so risk is low.