Revert my file browser changes that affected search

[sakertooth]

Due to the unusual bugs that were reported as well as the recent backlash from users (there was also backlash when I did this previously), my plan is to revert my changes that affected search behavior in the file browser. I'm no longer confident in my ability to do this properly, but if anything, it serves as a clean slate for anyone who wants to improve on search the right way.

I tried to fix all the merge conflicts when doing the revert appropriately, but if some mistake slipped through, let me know.

PS: Searching in samples, projects, etc, might be slow/choppy, while searching in root and home will most likely freeze the application. This was the main issue, but hopefully it'll be fixed properly without backlash later if this is merged.

Fixes #8142
Fixes #8401

[Monospace-V]

Works, but I've noticed a few issues right off the bat:

If I search for something, it automatically expands every folder where that is found and shows the results.

• When I backspace my search query, the folder remains expanded. (there is no button that will close all expanded folders and initialize the view of a sidebar tab)
  If I close every folder and then search again, it auto-expands while searching but the folders I closed become closed again when I backspace the search query.

• In the first search after opening LMMS (ie, you need to start a new LMMS window to notice this issue, it can only be observed once per LMMS session), if typing a single query in the searchbar, when backspacing the query, the search is still filtered by the part of the query most recently backspaced.
  for instance:

  • hat -> backspace thrice till empty: results are still filtered by "h"
  • hat -> ctrl-A and then backspace so it's all empty suddenly: results are still filtered by "hat")

I suspect these are related, but isn't everything related in a codebase anyway? My suspicions are rather unfounded.

Both issues can be observed in this recording:

lmms_kmMq9GpGA2.mp4

And obviously it crashes when searching in "My Computer" tab.

I do have a suggestion: If any drive in the My Computer tab is expanded, search only that drive, else search only one directory deep. However, I don't know whether this is possible. Stable does something that enables searching drives, but it is too cursed for me to understand presently.