In `FirmwareDownloader.DownloadFileAsync`, creating a new `HttpClient` per call can exhaust sockets. Consider reusing a static/shared `HttpClient` instance.

[julerobb1]

In FirmwareDownloader.DownloadFileAsync, creating a new HttpClient per call can exhaust sockets. Consider reusing a static/shared HttpClient instance.

Originally posted by @Copilot in #6 (comment)