Use ES module build of react-router-dom (#5264)

app/javascript/mastodon/containers/mastodon.js

...script/mastodon/features/account/components/action_bar.js

...pt/mastodon/features/compose/components/search_results.js

app/javascript/mastodon/features/compose/index.js

app/javascript/mastodon/features/home_timeline/index.js

...pt/mastodon/features/status/components/detailed_status.js

...javascript/mastodon/features/ui/components/column_link.js

app/javascript/mastodon/features/ui/components/tabs_bar.js

...ascript/mastodon/features/ui/util/react_router_helpers.js

config/webpack/shared.js