fix: Remove unnecessary Cloud SQL instance flag from backend deployment

Author: ChingEnLin

.github/workflows/google-cloudrun-docker.yml

@@ -74,7 +74,6 @@ jobs:
             DB_UNIX_SOCKET=/cloudsql/gen-lang-client-0698668474:europe-west1:querypal-db
           flags: |
             --port=8000
-            --add-cloudsql-instances=gen-lang-client-0698668474:europe-west1:querypal-db
             --allow-unauthenticated
 
       # Build and Push Frontend Container