Run scarb clean before scarb check in verify_cairo_listings.sh

scripts/verify_cairo_listings.sh

@@ -1,4 +1,4 @@
 #!/bin/bash
 set -e
 
-for d in ./docs/listings/*; do (cd "$d" && scarb check); done
+for d in ./docs/listings/*; do (cd "$d" && scarb clean &&  scarb check); done