supply presets url also when generating icons

Author: tyrasd

.github/workflows/build-preview.yml

@@ -26,6 +26,8 @@ jobs:
         working-directory: './iD'
       - run: npm run all
         working-directory: './iD'
+        env:
+          ID_PRESETS_CDN_URL: '../../'
       - run: npm run dist
         working-directory: './iD'
         env: