N+1 when resolving `read_code` permission on .com logged-in landing page

We noticed the logged-in view of the landing page spends 30% of all object allocations (hundreds of thousands of allocations) in testing a single permission:

This causes GC churn and unnecessary CPU time spent; the method resolving this permission was also on CPU for 24% of the time.

We found that this could be caused by an N+1, see this comment.