fix: resolve the issue of unable to delete pictures. (#9)

#### What type of PR is this?

/kind bug

#### What this PR does / why we need it:

修复移除已添加图片时，由于变量名错误导致图片无法移除的问题。

#### Which issue(s) this PR fixes:

Fixes #7 

#### Special notes for your reviewer:

测试方式：

1. 安装可测试插件 [plugin-moments-1.0.0-SNAPSHOT.jar.zip](https://github.com/halo-sigs/plugin-moments/files/11147044/plugin-moments-1.0.0-SNAPSHOT.jar.zip)
2. 前往瞬间页面添加图片
3. 点击删除按钮，查看是否能够正常移除已添加图片

#### Does this PR introduce a user-facing change?

```release-note
修复无法移除已添加图片的问题。
```

console/src/components/MomentEdit.vue

@@ -215,7 +215,7 @@ const removeMedium = (media: MomentMedia) => {
   if (!formMedium) {
     return;
   }
-  let index: number = formMedium.indexOf(medium);
+  let index: number = formMedium.indexOf(media);
   if (index > -1) {
     formMedium.splice(index, 1);
   }