feat: 优化填充组图层背景命令，支持实时更新和撤销功能，改进填充对象的处理逻辑

src/component/Canvas/CanvasEditor/managers/ThumbnailManager.js

@@ -143,18 +143,18 @@ export class ThumbnailManager {
     const objectsWithZIndex = [];
 
     layersToRasterize.forEach((layer) => {
-      if (layer.fill) {
-        const { object } = findObjectById(this.canvas, layer.fill.id);
-        if (object) {
-          // 获取对象在画布中的z-index（数组索引）
-          const zIndex = allCanvasObjects.indexOf(object);
-          objectsWithZIndex.push({
-            object: object,
-            zIndex: zIndex,
-            layerObj: layer.fill,
-          });
-        }
-      }
+      // if (layer.fill) {
+      //   const { object } = findObjectById(this.canvas, layer.fill.id);
+      //   if (object) {
+      //     // 获取对象在画布中的z-index（数组索引）
+      //     const zIndex = allCanvasObjects.indexOf(object);
+      //     objectsWithZIndex.push({
+      //       object: object,
+      //       zIndex: zIndex,
+      //       layerObj: layer.fill,
+      //     });
+      //   }
+      // }
 
       if (layer.fabricObject) {
         // 如果图层本身有fabricObject，直接添加