Is your feature request related to a problem? Please describe.

Imagine the following helper:

module ButtonHelper
  class Button
    def initialize(text:)
      @text = text
    end
  end

  def button(**)
    render Button.new(**)
  end
end

Currently rubocop returns the offense Rails/HelperInstanceVariable: Do not use instance variables in helpers.

Describe the solution you'd like

Rubocop should analyze whether the use of the instance variable occurs within a class, in which case it should ignore it.