ci(core): Reduce memory usage in tests (part-2) (no-changelog) (#7671)

This also gets rid of `Db.collection`, which was another source of
circular dependencies.

.github/workflows/units-tests-reusable.yml

@@ -60,6 +60,9 @@ jobs:
       - name: Test Backend
         run: pnpm test:backend
 
+      - name: Test Nodes
+        run: pnpm test:nodes
+
       - name: Test Frontend
         run: pnpm test:frontend