Windows: Don't display error dialogs

Summary:
Some Windows API functions like GetDiskFreeSpaceEx may produce error
dialogs. This is not desired. Fix this by temporarily blocking errors by
calling SetThreadErrorMode with certain error suppressing flags.

BUG: 371012
FIXED-IN: 5.28.0

Reviewers: #frameworks, brauch, vonreth

Reviewed By: vonreth

Subscribers: vonreth, nalvarez, broulik

Differential Revision: https://phabricator.kde.org/D3091