webpack bundle: remove presumably unnecessary warnings

Those "Conflicting order" warnings can be safely ignored in projects "where css ordering
has been mitigated through consistent use of scoping or naming conventions", which should
be our case with Svelte.

Those warnings appeared in c6b864e due to the addition of a new dependency to works_browser_section.svelte:
  import WorkActions from '#entities/components/layouts/work_actions.svelte'

Related issue: facebook/create-react-app#5372 (comment)

bundle/plugins/extract_css.cjs

@@ -3,4 +3,6 @@ const MiniCssExtractPlugin = require('mini-css-extract-plugin')
 module.exports = new MiniCssExtractPlugin({
   filename: '[name].[contenthash:8].css',
   chunkFilename: '[name].[contenthash:8].css',
+  // See https://github.com/webpack-contrib/mini-css-extract-plugin#ignoreOrder
+  ignoreOrder: true,
 })