Remove unused `statuses#embed` body class assignment (#31787)

app/controllers/statuses_controller.rb

@@ -11,7 +11,6 @@ class StatusesController < ApplicationController
   before_action :require_account_signature!, only: [:show, :activity], if: -> { request.format == :json && authorized_fetch_mode? }
   before_action :set_status
   before_action :redirect_to_original, only: :show
-  before_action :set_body_classes, only: :embed
 
   after_action :set_link_headers
 
@@ -51,10 +50,6 @@ class StatusesController < ApplicationController
 
   private
 
-  def set_body_classes
-    @body_classes = 'with-modals'
-  end
-
   def set_link_headers
     response.headers['Link'] = LinkHeader.new(
       [[ActivityPub::TagManager.instance.uri_for(@status), [%w(rel alternate), %w(type application/activity+json)]]]