Restore VS2022 support (#13524)
Fix-up of #13387
Fixes #13033
Summary of the issue:
Pr #13387 introduced support for custom UIA extensions, there by using the Microsoft UIA Automation remote operations library. This pr disabled building support for Visual Studio 2022. This has now been solved.
Description of how this pull request fixes the issue:
Fixes build on Visual Studio 2022 by ensuring that the windir environment variable is available. This should eventually be fixed in scons itself, though there's a note in their source code stating that adding environment variables to the basic set that's imported from os.environ should be considered very carefully.
