tools/update-responses/download_missing_versions fails to download OSX mar files

When running make incrementals, the download of the mar files from the previous version (if not already present) fails. The reason is that the OSX mar files now contain code signing, and don't match the checksum of the sha256sums-unsigned-build.txt file.

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information