Missing sites return an ItemNotFound error code,
which we aren't currently handling when doing
queries for individual sites. This change catches that error code and stacks the error with a
resourceOwnerNotFound sentinel.
---
#### Does this PR need a docs update or release note?
- [x] ⛔ No
#### Type of change
- [x] 🐛 Bugfix
#### Test Plan
- [x] 💪 Manual
- [x] 💚 E2E