Fix wrong default for `jsBundleAssetPath` on `DefaultReactHost` (#53546)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53546

The default for `DefaultReactHost.getDefaultReactHost(...,jsBundleAssetPath,...)` is wrong.
The default should be `index.android.bundle`.

That's the same value we had for the same field in ReactNativeHost:
https://www.internalfb.com/code/fbsource/[76a814c7d27036f7056c9f2c7e1370746ed4ccd4]/xplat/js/react-native-github/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactNativeHost.java?lines=225-227

Having just `index` as default cause the app to instacrash on release because the bundle can't be found.

Reviewed By: fabriziocucci

Differential Revision: D81435921

fbshipit-source-id: ea871f771fd61e9d838a800e988f2edc308ec8ea