docs: Remove broken links

Author: igorlukanin

docs/pages/product/getting-started/cloud/query-from-react-app.mdx

@@ -80,12 +80,5 @@ const { resultSet, isLoading, error, progress } = useCubeQuery({
 });
 ```
 
-For more information on the Cube JavaScript frontend package and integration
-with React, please refer to the documentation.
-
-You can also explore example applications built with React on top of the Cube
-REST API, along with their source code.
-
-- [React with Highcharts](https://highcharts-demo.cube.dev/#/)
-- [React with AG Grid](https://react-pivot-table-demo.cube.dev/#/)
-- [React query builder](https://react-dashboard-demo.cube.dev/#/)
+For more information on the JavaScript SDK and integration
+with React, please refer to the documentation.

docs/pages/product/getting-started/databricks/query-from-react-app.mdx

@@ -75,12 +75,5 @@ const { resultSet, isLoading, error, progress } = useCubeQuery({
 });
 ```
 
-For more information on the Cube JavaScript frontend package and integration
-with React, please refer to the documentation.
-
-You can also explore example applications built with React on top of the Cube
-REST API, along with their source code.
-
-- [React with Highcharts](https://highcharts-demo.cube.dev/#/)
-- [React with AG Grid](https://react-pivot-table-demo.cube.dev/#/)
-- [React query builder](https://react-dashboard-demo.cube.dev/#/)
+For more information on the JavaScript SDK and integration
+with React, please refer to the documentation.