[LiveSync] allow for custom files (extensions) to be handled by liveSync

In my app i need to allow fast live sync for files ".mss"
When those files are changed (in assets), only a reload of the map style is needed.
I already handle that through global.__onLiveSync

But now it does not work anymore. It comes from that line:
https://github.com/NativeScript/nativescript-cli/blob/5069f29fcb0a1dc9abbf3eb5523b298141bb3b11/lib/services/webpack/webpack-compiler-service.ts#L59

I was working a few releases before. If i

Here only files with 'hot-update' will allow live sync. How can i make it work?
Actually how does it work today for images live sync. I can see that it is supposed to be handled seeing fastLivesyncFileExtensions:
https://github.com/NativeScript/nativescript-cli/blob/9320a1de8462e8451f08a4798d35912573f78ac3/lib/services/android-project-service.ts#L85

先閱讀 lib/services/webpack/webpack-compiler-service.ts 第 59 行附近的內容，並與 lib/services/android-project-service.ts 第 85 行附近的內容比較，尤其是 fastLivesyncFileExtensions。追蹤影像變更如何到達 liveSync，以及 global.__onLiveSync 如何參與其中。完成的標準是：自訂 .mss asset 的變更會觸發必要的 liveSync 行為，同時不影響現有的影像處理。