+default/search-project removes preview from +vertico/project-search

### I confirm that...

- [X] I have searched the [issue tracker](https://github.com/doomemacs/doomemacs/issues), [documentation](https://docs.doomemacs.org), [FAQ](https://docs.doomemacs.org/-/faq), [Discourse](https://discourse.doomemacs.org), and [Google](https://google.com), in case this issue has already been reported/resolved.

- [X] I have read "[How to Debug Issues](https://doomemacs.org/d/how2debug)", and will use it to provide as much information about this issue as possible.

- [X] The issue can be reproduced on the **latest** available commit of Doom.

- [X] The issue can be reproduced on a stable release of Emacs, such as 27 or 28. *(Doom does not support development builds like 29+ or any version ending in .50 or .9x)*

### Expected behavior

I consider that +default/search-project has the same behavior as +vertico/project-search.

### Current behavior

The function +default/search-project does not preview the buffer when selecting a result. The function +vertico/project-search does instantly preview the search result when selecting a result.

### Steps to reproduce

1. Run `+default/search-project`
2. Search `xyz`
3. Select a result with `C-j` or `up` (the result is NOT previewed)
4. Run `+vertico/project-search`
5. Search `xyz`
6. Select a result with `C-j` or `up` (the result is previewed in a buffer)

### System Information

https://pastebin.com/ubLpPde1