Ability to disable opening the file when selecting widget from Widget Explorer

In VS Code, when I am only interested in viewing the widget in the Layout Explorer, opening the file takes a lot of space + it moves all panes in undesirable way.

It'd be nice to have a way to disable the `file opener` or have a separate action to open the file (right click menu or cmd+click combination).

```
devtools version: 2.25.0
VS Code version: 1.83.1
Dart extension: v3.74.0
```

首先，在 Dart DevTools 代码库中追踪 Widget Explorer 的文件打开器行为，并查看 issue 讨论以了解预期的交互。比较禁用打开器与使用单独的打开文件操作这两种方式，然后验证选择 widget 时可以不影响 Layout Explorer 的窗格，同时文件仍可通过所选操作访问。

由索引模型根据 Issue 内容生成。