pages: Fix "undefined local variable or method `total_size'" when maximum page size is exceeded

app/services/projects/update_pages_service.rb

@@ -85,7 +85,7 @@ module Projects
       public_entry = build.artifacts_metadata_entry(SITE_PATH, recursive: true)
       if public_entry.total_size > max_size
-        raise "artifacts for pages are too large: #{total_size}"
+        raise "artifacts for pages are too large: #{public_entry.total_size}"
       end
       # Requires UnZip at least 6.00 Info-ZIP.