Simplify using helper methods in components

The `use_helpers` method was added in ViewComponent 3.8.0, and it's
included by default in all components since version 3.11.0.

Note we sometimes delegated the `can?` method to the controller instead
of the helpers, for no particularly reason. We're unifying that code as
well.

app/components/attachable/fields_component.rb

@@ -1,6 +1,6 @@
 class Attachable::FieldsComponent < ApplicationComponent
   attr_reader :f, :resource_type, :resource_id, :relation_name
-  delegate :current_user, :render_image, to: :helpers
+  use_helpers :current_user, :render_image
 
   def initialize(f, resource_type:, resource_id:, relation_name:)
     @f = f