Remove free pass on grunt task

Author: martignoni

.github/workflows/ci.yml

@@ -106,10 +106,9 @@ jobs:
         if: ${{ always() }}
         run: moodle-plugin-ci mustache
 
-      # At this stage, assume this succeeds.
       - name: Grunt
         if: ${{ always() }}
-        run: moodle-plugin-ci grunt --max-lint-warnings 0 || true
+        run: moodle-plugin-ci grunt --max-lint-warnings 0
 
       - name: PHPUnit tests
         if: ${{ always() }}