add `VITE_VERSION_TO_TEST` environment variable to control what version of vite is used for the vite plugin playground tests#10900

dario-piotrowicz wants to merge 2 commits intomaincloudflare/workers-sdk:mainfrom

dario/DEVX-2232/vite-playground-different-versionscloudflare/workers-sdk:dario/DEVX-2232/vite-playground-different-versionsCopy head branch name to clipboard