Automatic merge from submit-queue (batch tested with PRs 39169, 40719, 38954, 40808, 40689)

Exports KUBE_TEMP for use in Vagrantfile

In #40147, the logic for setting `KUBE_TEMP` was refactored into `common.sh`. However, it was overlooked that `KUBE_TEMP` [needs to be exported for vagrant to work properly](https://github.com/kubernetes/kubernetes/pull/40147/files#diff-b19d3d93456020e2168c7f304f722969).

This PR restores the `export` so that `Vagrantfile` can use `ENV["KUBE_TEMP"]` properly.

👀 @rthallisey @shyamjvs @timothysc