Variables not showing in "Docs" section.

### Expected Behavior

Variables works as expected.

### Actual Behavior

### Reproduction Steps

1. Create doc for any request
2. Insert any variable
3. Click preview

### Is there an existing issue for this?

- [X] I have searched the [issue tracker](https://www.github.com/Kong/insomnia/issues) for this problem.

### Additional Information

_No response_

### Insomnia Version

2023.5.6

### What operating system are you using?

macOS

### Operating System Version

Ventura 13.2.1

### Installation method

download from insomnia

### Last Known Working Insomnia version

_No response_

Reproduce the problem in Insomnia by creating a document for a request, inserting a variable, and opening its preview. Compare the preview with the request and variable configuration shown in the attached screenshots; done means the inserted variable is rendered in the Docs preview.

Written by the indexing model from the issue text.