fix(gatsby-plugin-gatsby-cloud): fix cloud being bundled (#31604)

(cherry picked from commit 4a62a20)

Author: wardpeet

packages/gatsby-plugin-gatsby-cloud/package.json

@@ -44,6 +44,7 @@
     "url": "https://github.com/gatsbyjs/gatsby.git",
     "directory": "packages/gatsby-plugin-gatsby-cloud"
   },
+  "sideEffects": false,
   "scripts": {
     "build": "babel src --out-dir . --ignore \"**/__tests__\"",
     "prepare": "cross-env NODE_ENV=production npm run build",