Error on down site should be a warning for the user

I get `error uploading: HTTPSConnectionPool(host='eu.i.posthog.com', port=443): Max retries exceeded with url: /batch/ (Caused by NewConnectionError(': Failed to establish a new connection: [Errno -2] Name or service not known'))` with error style.

This should be a warning since it doesn't prevent using FreeCAD or any addon. The text should also be more user-friendly.

Start by tracing the telemetry upload error handling for the reported HTTPSConnectionPool failure and identify where the error-style message is produced. Check how the FreeCAD addon behaves when the site is unavailable, then verify that the message is presented as a user-friendly warning and that normal FreeCAD and addon use remains unaffected.

Written by the indexing model from the issue text.