[FIX] Attributes: remove the set value in a getter method.

Author: Gorash

packages/plugin-xml/src/Attributes.ts

@@ -99,14 +99,11 @@ export class Attributes extends Modifier {
               })
             : [];
         if (this.classList.length && !keys.includes('class')) {
-            // The node was not parsed with a class attribute, add it in place.
-            // Use `get` for its value but record its position in the record.
-            this._record.class = null;
+            // The node was not parsed with a class attribute.
             keys.push('class');
         }
         if (this.style.length && !keys.includes('style')) {
-            // The node was not parsed with a style attribute, keep it always at
-            // the end of the attributes list.
+            // The node was not parsed with a style attribute.
             keys.push('style');
         }
         return keys;