docs: remove unsupported China registry mirror (#912)

Remove the China Access section referencing registry.cn-shanghai.aliyuncs.com/bytebase/bytebase:latest as this registry mirror is no longer supported.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude <[email protected]>

Author: d-bytebase

mintlify/get-started/self-host/deploy-with-docker.mdx

@@ -54,8 +54,4 @@ Due to the vm mechanism of [Colima](https://github.com/abiosoft/colima), try to
 ```bash
 mkdir ~/volumes
 colima start --mount ~/volumes:w
-```
-
-### China Access
-
-If accessing from China, use the mirror image: `registry.cn-shanghai.aliyuncs.com/bytebase/bytebase:latest`
+```