[FR] Firebase Storage Emulator Support

As per https://firebase.google.com/docs/emulator-suite/install_and_configure#admin_sdk_availability the current version of the Firebase Admin SDK for Java does not yet provide support for Firebase Storage Emulator.

Indeed, even after setting `FIREBASE_STORAGE_EMULATOR_HOST` in my environment as per https://firebase.google.com/docs/emulator-suite/connect_storage#admin_sdks, that endpoint is simply ignored and requests are still sent to the usual remote URL(https://storage.googleapis.com/storage/v1...)

Is there a rough time horizon, in which this feature will be implemented?

从 issue 中的 Firebase 文档链接开始，尤其是“Admin SDK availability”和“Storage Emulator connection”部分，然后追踪 Java Admin SDK 如何选择 Storage 请求端点。报告中没有提到 repository 文件或测试；完成标准是 FIREBASE_STORAGE_EMULATOR_HOST 将 Storage 请求路由到 emulator，而不是 storage.googleapis.com，并为该行为提供测试覆盖。

由索引模型根据 Issue 内容生成。