Merge commit 'dc09c10fa8cc9230bf14e48d790c8f0c26043f8f' into glitch-soc/merge-upstream

Conflicts:
- `.rubocop_todo.yml`:
  Upstream re-generated the file, while glitch-soc has a specific ignore
  for some file.
  Updated the file as upstream did and kept our extra ignore.
- `config/webpack/shared.js`:
  Upstream added a plugin, but our files are pretty different.
  Added the plugin as well.
- `spec/helpers/application_helper_spec.rb`:
  Upstream refactored tests, but part of them were different because
  of glitch-soc's theming system.
  Applied the refactoring to glitch-soc's change.

app/lib/importer/base_importer.rb

@@ -68,8 +68,8 @@ class Importer::BaseImporter
 
   protected
 
-  def in_work_unit(*args, &block)
-    work_unit = Concurrent::Promises.future_on(@executor, *args, &block)
+  def in_work_unit(...)
+    work_unit = Concurrent::Promises.future_on(@executor, ...)
 
     work_unit.on_fulfillment!(&@on_progress)
     work_unit.on_rejection!(&@on_failure)