General: Pass on the return value from `wp_redirect()` for `wp_safe_redirect()`.

This brings the behaviour of the two functions in line with each other.

Props Drivingralle

Fixes 42108

Built from https://develop.svn.wordpress.org/trunk@42206


git-svn-id: https://core.svn.wordpress.org/trunk@42035 1a063a9b-81f0-0310-95a4-ce76da25c4cd