Remove `Alpine 3.16` from the runner images section in the Advanced Configuration doc
What does this MR do?
Remove Alpine 3.16 from the runner images section in the Runner Advanced Configuration document. Refer to the [container images and end of publishing date doc](https://docs.gitlab.com/runner/install/support-policy.html#container-images-and-end-of-publishing-date.
Why was this MR needed?
Documentation review and update for KR 8511