Move default embed size knowledge into OEmbedSerializer (#31990)

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

app/controllers/api/oembed_controller.rb

@@ -7,7 +7,7 @@ class Api::OEmbedController < Api::BaseController
   before_action :require_public_status!
 
   def show
-    render json: @status, serializer: OEmbedSerializer, width: maxwidth_or_default, height: maxheight_or_default
+    render json: @status, serializer: OEmbedSerializer, width: params[:maxwidth], height: params[:maxheight]
   end
 
   private
@@ -23,12 +23,4 @@ class Api::OEmbedController < Api::BaseController
   def status_finder
     StatusFinder.new(params[:url])
   end
-
-  def maxwidth_or_default
-    (params[:maxwidth].presence || 400).to_i
-  end
-
-  def maxheight_or_default
-    params[:maxheight].present? ? params[:maxheight].to_i : nil
-  end
 end