Sidebar search no longer shows directory trees

### System Information

Windows 11

### LMMS Version(s)

master

### Most Recent Working Version

stable; alpha

### Bug Summary

Issue was caused after #7679.
When searching for projects in the sidebar, directory trees are no longer shown and there is no way to view the full directory anymore.
I have directories because I use directories [sorting, categorize, some preset/sample libraries need attribution and I avoid using them in some projects, convenience, etc]
Considering the attribution case, I think users would actively benefit from directories being visible.

**Users who don't want directories typically don't use directories.**

You cannot tell if a file is in "Demos," or in a folder labelled "Do not remix," or in a folder called "corrupted versions," or your own project. You cannot tell if a kick sample is in a folder called "attribute these samples" or in a folder called "rock kit 80s" to pick samples from the same kit or easily pick certain samples, or if it is from a folder called "low quality samples".

### Expected Behaviour

My directories that I decided to place in my own folder for my own organization are visible and organizing when I search.

Directories can be minimized and I can see my directories that I sorted my things into.

### Steps To Reproduce

Create a file. Place a version of it inside a directory and one outside. Place both the file and the directory in your LMMS projects folder.
Search the folder. You cannot tell the difference between a file in a directory and a file outside it.

You now need to right-click on each file and see the nearly-invisible and unexpandable shortened-to-width filepath on each single entry to see the directory in which you yourself placed your own file.

**You cannot even minimize large directories anymore!**

???

### Logs

_No response_

### Screenshots / Minimum Reproducible Project

non-informative randomly ordered projects, **repeated files/folders with no context**, my own organization of files is disregarded

unusable invisible directory path that can be obtained from right-clicking each single result

extremely long result sets that cannot be minimized into directories

If I wanted results without directories I would place my files without directories.
If this is behaviour that anyone desires then users would benefit from a toggle between the old behaviour and new behavior.

### Please search the issue tracker for existing bug reports before submitting your own.

- [x] I have searched all existing issues and confirmed that this is not a duplicate.

Reproduce the sidebar search behavior on master using the listed steps, then compare it with stable or alpha and inspect the changes from #7679. Confirm how directory results are represented and whether they can be expanded or minimized. Done means search results show directory context and preserve the user's folder organization without losing file results.

Written by the indexing model from the issue text.