Run the vulnerability scan on the local grid

The testing grid is missing users.nix but the local grid has it.

ci-tools/vulnerability-scan

@@ -21,7 +21,7 @@ OUTPUT=$1
 [ -e scan-target ] && rm -v scan-target
 nix-shell --run '
 set -x
-if morph_result=$(morph build morph/grid/testing/grid.nix 2>&1); then
+if morph_result=$(morph build morph/grid/local/grid.nix 2>&1); then
   object=$(echo "$morph_result" | tail -n 1)
   ln -s "$object" scan-target
 else