This is called out on the Flutter website, but it still comes up now and then (for ex. #2222).

Since the failure is not always obvious (especially since it may appear to work from a terminal - if that terminal is running elevated), we should show a warning. We can use the env variables (see https://pureinfotech.com/list-environment-variables-windows-10/) to get the problematic locations, and do a case-insensitive startsWith against the SDK.