uui-css: ensure that uui-css is clean before building new files

Author: iOvergaard

package.json

@@ -42,7 +42,7 @@
     "lerna-fix": "lerna exec -- node ../../scripts/lerna-fix.mjs",
     "lerna:modify-package": "lerna exec -- node ../../scripts/modify-pkgjson.mjs",
     "postinstall": "npm run bootstrap",
-    "bootstrap": "lerna run --scope @umbraco-ui/uui-css build && node ./scripts/generate-ts-config.js",
+    "bootstrap": "lerna run --scope @umbraco-ui/uui-css clean && lerna run --scope @umbraco-ui/uui-css build && node ./scripts/generate-ts-config.js",
     "prepare": "husky install",
     "new-package": "plop && npm i",
     "pack-all": "npm run build:prod && node ./scripts/pack-packages.js",