Fix: suppress docker-compose warning (#8698)

### What problem does this PR solve?

Suppress docker-compose warning like:

```bash
The "HF_ENDPOINT" variable is not set. Defaulting to a blank string.
The "MACOS" variable is not set. Defaulting to a blank string.
The "SANDBOX_EXECUTOR_MANAGER_IMAGE variable is not set. Defaulting to a blank string.
The "SANDBOX_EXECUTOR_MANAGER_PORT variable is not set. Defaulting to a blank string.
```

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)
- [x] Refactoring

docker/docker-compose-base.yml

@@ -107,10 +107,10 @@ services:
     container_name: ragflow-sandbox-executor-manager
     profiles:
       - sandbox
-    image: ${SANDBOX_EXECUTOR_MANAGER_IMAGE}
+    image: ${SANDBOX_EXECUTOR_MANAGER_IMAGE-infiniflow/sandbox-executor-manager:latest}
     privileged: true
     ports:
-      - ${SANDBOX_EXECUTOR_MANAGER_PORT}:9385
+      - ${SANDBOX_EXECUTOR_MANAGER_PORT-9385}:9385
     env_file: .env
     volumes:
       - /var/run/docker.sock:/var/run/docker.sock

docker/docker-compose.yml

@@ -38,8 +38,8 @@ services:
     env_file: .env
     environment:
       - TZ=${TIMEZONE}
-      - HF_ENDPOINT=${HF_ENDPOINT}
-      - MACOS=${MACOS}
+      - HF_ENDPOINT=${HF_ENDPOINT-}
+      - MACOS=${MACOS-}
     networks:
       - ragflow
     restart: on-failure