Revert "docker: expose redis port so the app can connect to it"

This reverts commit d4e1123ea7.

docker-compose.yml

@@ -74,8 +74,6 @@ services:
     restart: unless-stopped
     env_file:
       - ./.env
-    ports:
-      - "6379:6379"
     volumes:
       - "redis-data:/data"
     networks: