Discrepancy between project chooser and project folder context menu re setting as active project

### What Happened?

Clicked on project chooser button and noticed a folder that was not a git repository appeared in the list. This conflicts with the context menu item for that project folder item which did not have a "Set as Active Project" item

### Steps to Reproduce

Open a git project
Open another folder, not a git project
See context menus
See ProjectChooser dropdown

### Expected Behavior

It needs to be decided whether "active project" can reasonable be anything other than a git repository. Many actions only make sense for a git repository. The projectchooser and the context menu should agree whether a folder can be made active project.

### OS Version

8.x (Circe)

### Session Type

Classic Session (X11, This is the default)

### Software Version

Latest release (I have run all updates)

### Log Output

```shell

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### Hardware Info

_No response_

打开一个 git 项目和一个非 git 文件夹来复现该差异，然后将 ProjectChooser 下拉菜单与每个文件夹的上下文菜单进行比较。首先确定是否应允许非 git 文件夹作为活动项目；当两个入口点都一致地应用这一决定时，即视为完成。

由索引模型根据 Issue 内容生成。