Spike: Review generated bundles for code splitting or dependency optimizations

Created by: umpox

Review our existing bundles generated from a production build.

Look for any further optimisations we can make through code splitting, changing dependencies, or changing our Webpack config.

We should be able to utilise yarn analyze-bundle for this: https://sourcegraph.com/github.com/sourcegraph/sourcegraph@main/-/blob/client/web/package.json#L33:36