Delete unused scripts/upload.py (#21482)#21503

ti-chi-bot wants to merge 1 commit intopingcap:release-8.1pingcap/docs-cn:release-8.1from

ti-chi-bot:cherry-pick-21482-to-release-8.1ti-chi-bot/docs-cn:cherry-pick-21482-to-release-8.1Copy head branch name to clipboard