Fix web-example

[m-bert]

Summary

Following the transition to a monorepo structure, our web-example app stopped working due to an asset loading issue. Turns out that the getAssetByID function from react-native-web was being called from the incorrect module. We believe this might have resulted in one module blocking an asset while another module was trying to load it, causing the application to crash.

This PR modifies the metro.config.js inside the web-example folder. It is now configured to ignore the @react-native module from the root, which allows assets to load correctly.

Test plan

Run web-example.