upgrade: sandbox to 0.2.6 (#7410)

docker/docker-compose.middleware.yaml

 
   # The DifySandbox
   sandbox:
-    image: langgenius/dify-sandbox:0.2.1
+    image: langgenius/dify-sandbox:0.2.6
     restart: always
     environment:
       # The DifySandbox configurations

docker/docker-compose.yaml

 
   # The DifySandbox
   sandbox:
-    image: langgenius/dify-sandbox:0.2.1
+    image: langgenius/dify-sandbox:0.2.6
     restart: always
     environment:
       # The DifySandbox configurations