Revert "nix: default output to scopeHostStatic instead of scopeHost"

This reverts commit a37b2b9.

Dynamic builds are working again, so we'd prefer having that be the
default output for consistency with nixpkgs.

flake.nix

@@ -119,7 +119,7 @@
     in
     {
       packages = {
-        default = scopeHostStatic.main;
+        default = scopeHost.main;
         hmalloc = scopeHost.main.override { features = ["hardened_malloc"]; };
 
         oci-image = scopeHost.oci-image;