On Wednesday, we agreed to publish only a smaller set of security docs to maximize the effort on `main`.

This PR updates the 3.2 version of the downstream doc import list yaml file in the upstream community to remove the unrequired content so that our downstream import script does not automatically add the content downstream and so that the xrefs get turned into external community links.

FYI @gsmet / @gastaldi / @aloubyansky / @maxandersen

Please note, I deliberately targeted the 3.2 branch instead of main because the version of this file on main has diverged significantly. Several files have been renamed/restructured requiring a massive backport, most of which seems to be currently outside the scope of the 3.2 docs both upstream and downstream. Thanks.