Make use of render_not_found to simplify 404 response

Co-authored-by: Martin Emde <[email protected]>

app/controllers/profiles_controller.rb

@@ -9,15 +9,8 @@ class ProfilesController < ApplicationController
 
   def show
     @user = User.find_by_slug!(params[:id])
-    return @rubygems = @user.rubygems_downloaded.includes(%i[latest_version gem_download]).strict_loading if @user.email_confirmed?
-    respond_to do |format|
-      format.any do
-        render plain: t(:this_rubygem_could_not_be_found), status: :not_found
-      end
-      format.html do
-        render file: Rails.public_path.join("404.html"), status: :not_found, layout: false, formats: [:html]
-      end
-    end
+    return render_not_found unless @user.email_confirmed?
+    @rubygems = @user.rubygems_downloaded.includes(%i[latest_version gem_download]).strict_loading
   end
 
   def me