Fix large image overflow in comment page (#31740)

Fix large image overflow in comment page (#31740)

Close #31709

52px is calculate by avatar size in
templates\repo\issue\view_content\comments.tmpl
```html
<img src="{{.Poster.AvatarLink $.Context}}" width="40" height="40">
```
+
```css
.ui.comments .comment > .avatar ~ .content {
  margin-left: 12px;
}
```

![圖片](https://github.com/user-attachments/assets/bf15f4d4-1574-46f6-9f5e-1fbdbf1a98b0)

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Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>