Thanks for the heads up @dwhitemv! One minor correction - to keep the old behavior, you should set MB_NOTIFICATION_TEMP_FILE_SIZE_MAX_BYTES to 0. The variable MB_ENFORCE_NOTIFICATION_TEMP_FILE_SIZE_LIMIT briefly existed in the PR that shipped this feature, but it did not make it to the release.
We strongly recommend against this though, since it can easily make Metabase go into a crash loop if it has a particularly expensive query that makes it run out of memory. Returning less data or a summary is the better option.