fix: npm run dev-server error resolved (#23702)

CONTRIBUTING.md

@@ -585,6 +585,15 @@ There are three types of assets you can build:
 2. `npm run dev-server`: local development assets, with sourcemaps and hot refresh support
 3. `npm run build-instrumented`: instrumented application code for collecting code coverage from Cypress tests
 
+If this type of error comes while building assets(i.e using above commands):
+```bash
+Error: You must provide the URL of lib/mappings.wasm by calling SourceMapConsumer.initialize
+```
+Then put this:
+```bash
+export NODE_OPTIONS=--no-experimental-fetch`
+```
+
 #### Webpack dev server
 
 The dev server by default starts at `http://localhost:9000` and proxies the backend requests to `http://localhost:8088`.