`winget source update` returns success (0) when it fails

Brief description of your issue

The CDN being (at least partially) broken (#2666) seems like an unhandled exception in winget-cli, as it returns success / %errorlevel 0, no?

Following running in CMD as admin should not return success IMO.

C:\Windows\system32>winget source reset --force && winget source update && echo %errorlevel%
Resetting all sources...Done
Updating all sources...
Updating source: msstore...
Done
Updating source: winget...
Cancelled
0

C:\Windows\system32>

Steps to reproduce

Change DNS to replicate CDN being down?

Expected behavior

If sources can't in fact be updated, it should return an error.

Actual behavior

Says updating sources failed, but exit code 0 = success.

Environment

Windows Package Manager v1.3.2691
Copyright (c) Microsoft Corporation. All rights reserved.

Windows: Windows.Desktop v10.0.19045.2130
System Architecture: X64
Package: Microsoft.DesktopAppInstaller v1.18.2691.0

Start by tracing the winget source update command's failure handling and how its result becomes the process exit code. Reproduce the issue with a source or CDN failure, then verify that a failed update reports a nonzero exit code while a successful update still returns 0.