workflows/test.yml: specify CI=true (#29440)

Author: XhmikosR

.github/workflows/test.yml

@@ -39,6 +39,8 @@ jobs:
 
       - name: Install npm dependencies
         run: npm install
+        env:
+          CI: true
 
       - name: Install bundler dependencies
         run: bundle install --deployment --jobs=3 --retry=3 --clean