Updated core CI to build test dep

Author: BobDickinson

.github/workflows/core_tests.yml

@@ -23,6 +23,9 @@ jobs:
       - name: Install dependencies
         run: npm ci --ignore-scripts
 
+      - name: Build test package
+        run: npm run build-test
+
       - name: Build core
         run: npm run build-core