fix(@vben/plugins): extract URL from response in image upload callback

The upload callback was incorrectly passing the AxiosResponse object
to resolve() instead of extracting the actual image URL string.
This caused the editor to insert [object Object] as image src,
resulting in broken images.

playground/src/adapter/component/index.ts

@@ -734,7 +734,8 @@ async function initComponentAdapter() {
                 onProgress?.(percent);
               },
               onSuccess(response) {
-                resolve(response);
+                // 从响应中提取图片URL
+                resolve(response?.data?.url ?? response?.url ?? '');
               },
               onError() {
                 reject(new Error($t('ui.tiptap.upload.uploadFailed')));