[Bug] Hubble image build fails after introduce front-end download proxy

### Bug Type (问题类型)

None

### Before submit

- [X] I had searched in the [issues](https://github.com/apache/hugegraph-toolchain/issues) and found no similar issues.

### Environment (环境信息)

- Server Version: v1.x.x
- Toolchain Version: v1.x.x
- Data Size: xx vertices, xx edges

### Expected & Actual behavior (期望与实际表现)

https://github.com/hugegraph/actions/actions/runs/8103879676

### Vertex/Edge example (问题点 / 边数据举例)

_No response_

### Schema [VertexLabel, EdgeLabel, IndexLabel] (元数据结构)

_No response_

Start with the linked GitHub Actions run 8103879676 and inspect the Hubble image build logs around the front-end download proxy change. Trace the failing build step and reproduce it if possible; done means the Hubble image builds successfully with the proxy in place.

Written by the indexing model from the issue text.