fix: gracefully shutdown preview server on `SIGTERM` (fix #12990)

[elias-pap]

Description

fixes #12990

In the following manual tests the alias playground is opened in the left terminal, which runs the preview server. In the right terminal, a SIGTERM signal is sent (kill -15) to the left one. On the main branch, the preview command exits with code 1, and on the PR branch with code 0.

Main branch manual test:

https://github.com/vitejs/vite/assets/18152197/606267b4-c4c2-48c3-a449-9c7934aea779

PR branch manual test:

https://github.com/vitejs/vite/assets/18152197/d6ff2646-dcbb-4f64-a6d9-42379c2bcb38