Ensure pipewire-pulse is in the installer

In a real situation, the package is installed by a chain of recommends
pipewire-bin -> wireplumber -> pipewire-pulse and that chain is broken
either by debian-cd's dependency handling or by simple-cdd's logic to
build its local mirror. But this mention should ensure its presence in
the generated ISO.

simple-cdd/profiles/offline.downloads

@@ -11,3 +11,6 @@ xserver-xorg-video-vmware
 # Ensure unrar is available, otherwise the "unrar | unar" dependency
 # in kali-linux-headless ends up satisfied by the unar alternative
 unrar
+# Ensure pipewire-pulse is available so that when wireplumber gets
+# installed it can pull it as a recommends
+pipewire-pulse