This is a follow up to #132592, to ensure it doesn't happen again.

Before we extract the Dart SDK zip archive on windows, we move the existing output to a backup, and then extract zip to previous location of the old one. However, when a new file was added to this archive (LICENSE.dart_sdk_archive.md) but the powershell file to extract it wasn't updated, the 7zip sub-process that was spawned would prompt the user what they wanted to do about the conflict, but the powershell script would never surface this prompt to the user.

This was fixed by special-casing this file. However, we need a more robust solution to prevent this from happening again.