Disable runtime chunk fixes

https://github.com/1602/elm-app-webcomponent/blob/2faf510866c090c693207a08124e8b46761f2f4b/index.js#L36

https://github.com/halfzebra/create-elm-app/blob/6e023a5a5eb2f35ea4e03902ce3b410a84e67330/config/webpack.config.prod.js#L136

I think the option is called ` config.optimization.runtimeChunk` (without `s`).

Setting the chunk file name should then not be necessary anymore:
https://github.com/1602/elm-app-webcomponent/blob/2faf510866c090c693207a08124e8b46761f2f4b/index.js#L13

The issue points to index.js line 36 and line 13, and references a webpack config from another project. Start by examining the current webpack configuration in the repository to understand how runtimeChunk is set. The fix involves updating the property name and removing the unnecessary chunk filename setting. Check the webpack documentation for runtimeChunk to confirm the correct syntax. Verify the change by building the project.

索引モデルが issue の本文から書いたものです。