chore: Add Docker volume for test data in docker-compose.yml

This commit introduces a named volume `test_data` in the `docker-compose.yml` file for managing test-related data storage.

Author: vmeng-b

docker-compose.yml

@@ -6,4 +6,9 @@ services:
     container_name: flutter-web
     restart: unless-stopped
     ports:
-      - "8080:80"
+      - "8080:80"
+    volumes:
+      - test_data:/data
+
+volumes:
+  test_data: