[BE] 무중단 배포에서 health-check 부분을 추가한다. (#850)

.github/workflows/backend-prod-cd.yml

@@ -87,7 +87,9 @@ jobs:
       - name: Health check
         run: |
           for i in {1..2}; do
-            if curl -s http://localhost:8080/health-check | grep "200"; then
+            RESPONSE=$(curl -s -w "%{http_code}" -o /dev/null http://localhost:8080/health-check)
+            echo "Response: $RESPONSE"
+            if [ "$RESPONSE" -eq 200 ]; then
               echo "Health check passed"
               exit 0
             fi