Fixes #46723.

This simple PR allows OIDC users to choose to send one or more Clear-Site-Data directives after the logout request. Even though the PR is simple, I added a release/noteworthy-feature label to draw some attention to it since Clear-Site-Data is a rather new HTTP response header but which can be rather useful.
Also, this PR is done as part of the threat modelling activity.

I also did some minor, test-level only updates to fix a few logout constant names