docs: updated links for country map scripts (#19823)

docs/docs/miscellaneous/country-map-tools.mdx

@@ -54,8 +54,8 @@ The Country Maps visualization already ships with the maps for the following cou
 To add a new country to the list, you'd have to edit files in
 [@superset-ui/legacy-plugin-chart-country-map](https://github.com/apache-superset/superset-ui/tree/master/plugins/legacy-plugin-chart-country-map).
 
-1. Generate a new GeoJSON file for your country following the guide in [this Jupyter notebook](https://github.com/apache-superset/superset-ui/blob/master/plugins/legacy-plugin-chart-country-map/scripts/Country%20Map%20GeoJSON%20Generator.ipynb).
-2. Edit the countries list in [legacy-plugin-chart-country-map/src/countries.js](https://github.com/apache-superset/superset-ui/blob/master/plugins/legacy-plugin-chart-country-map/src/countries.js).
-3. Ping one of the Superset committers to get the `@superset-ui/legacy-plugin-chart-country-map` package published, or
-   publish it under another name yourself.
-4. Update npm dependencies in `superset-frontend/package.json` to install the updated plugin package.
+1. Generate a new GeoJSON file for your country following the guide in [this Jupyter notebook](https://github.com/apache/superset/blob/master/superset-frontend/plugins/legacy-plugin-chart-country-map/scripts/Country%20Map%20GeoJSON%20Generator.ipynb).
+2. Edit the countries list in [legacy-plugin-chart-country-map/src/countries.ts](https://github.com/apache/superset/blob/master/superset-frontend/plugins/legacy-plugin-chart-country-map/src/countries.ts).
+3. Install superset-frontend dependencies: `cd superset-frontend && npm install`
+4. Verify your countries in Superset plugins storybook: `npm run plugins:storybook`.
+5. Build and install Superset from source code.