Cleaned up unused package.json dependencies in site/custom

Author: winstonwumbo

src/boilerplate/site/custom/package.json

@@ -13,10 +13,7 @@
   },
   "devDependencies": {
     "rollup": "^2.0.0",
-    "rollup-plugin-terser": "7.0.2",
     "@rollup/plugin-node-resolve": "16.0.0",
-    "@web/rollup-plugin-html": "^2.3.0",
-    "rollup-plugin-rewrite-imports": "2.0.0",
     "@web/rollup-plugin-import-meta-assets": "^2.2.1",
     "rollup-plugin-esbuild": "6.1.1",
     "@rollup/plugin-babel": "6.0.4"