before docker-compose up, first down it,and cleans. (#9908)

### What problem does this PR solve?

_Briefly describe what this PR aims to solve. Include background context
that will help reviewers understand the purpose of the PR._

Fix the issue in ci.
[ci
err](https://github.com/infiniflow/ragflow/actions/runs/17452439789/job/49559702590?pr=9894)

```
 Container ragflow-redis  Error response from daemon: Conflict. The container name "/ragflow-redis" is already in use by container "b6cbde4d186ffba701f6e2a85f37e1d053d7197adb2938547f1df08cfcadf355". You have to remove (or rename) that container to be able to reuse that name.
Error response from daemon: Conflict. The container name "/ragflow-redis" is already in use by container "b6cbde4d186ffba701f6e2a85f37e1d053d7197adb2938547f1df08cfcadf355". You have to remove (or rename) that container to be able to reuse that name.
Error: Process completed with exit code 1.
```

### Type of change
- [x] Refactoring
- [x] Performance Improvement

Signed-off-by: zhanluxianshen <zhanluxianshen@163.com>

Author: zhanluxianshen

.github/workflows/tests.yml

@@ -67,6 +67,7 @@ jobs:
 
       - name: Start ragflow:nightly-slim
         run: |
+          sudo docker compose -f docker/docker-compose.yml down --volumes --remove-orphans
           echo -e "\nRAGFLOW_IMAGE=infiniflow/ragflow:nightly-slim" >> docker/.env
           sudo docker compose -f docker/docker-compose.yml up -d