chore: remove unused command

Co-authored-by: Matt Kane <matt.kane@netlify.com>

Author: Tiffany Le-Nguyen

package.json

@@ -12,7 +12,6 @@
     "cy:open": "cypress open --config-file cypress/config/all.json",
     "cy:run": "cypress run --config-file ../cypress/config/ci.json",
     "dev:demo": "next dev demo",
-    "dev:demo2": "next dev demo2",
     "format": "run-s format:check-fix:*",
     "format:ci": "run-s format:check:*",
     "format:check-fix:lint": "run-e format:check:lint format:fix:lint",