[Regression] [Windows] Desktop menu doesn't support drag and drop of .jpg anymore with the new bundled dlls.

Description

With 1.9.0 stable you were able to open the Desktop Menu and drag and drop .jpg for adding thumbnails, RetroArch would convert the files to .png and they would show without any issue. With 1.9.1 it's not possible anymore, you get this error instead:

[ERROR] [Qt]: Could not read image: C:\Users\B-S\Pictures\4x4 Evo (USA).jpg

I don't have this issue if I run RetroArch from my MSYS2 setup, so I used these command lines to copy the dlls: https://docs.libretro.com/development/retroarch/compilation/windows/#packaging-retroarch
and with these it works fine again! I uploaded them all here if anyone is interested: https://www.mediafire.com/file/3zv79bc4ai6cm5t/dlls.7z/file

Expected behavior

Drag and drop of .jpg to add a thumbnails with the Desktop Menu should work.

Actual behavior

It doesn't.

Steps to reproduce the bug

1. Start RetroArch and open Desktop Menu.
2. Go to a playlist, select a game and drag and drop a .jpg in bottom right to add a thumbnail.
3. It shouldn't do anything, and you should get an error in logs.
4. (optional) Download the dlls I bundled from the link in description, extract and overwrite existing dlls from RA folder and retry, it should work now.

Bisect Results

No idea, dlls bundled must have changed at some points in the buildbot but idk when.

Version/Commit

• RetroArch: 1.9.1 / 2fbcc99

Environment information

• OS: Windows 10

Start by reproducing the drag-and-drop failure in RetroArch's Windows Desktop Menu with the 1.9.1 bundled DLLs, then compare the packaged DLLs with the MSYS2-working set using the linked Windows packaging instructions. Done means JPEG files can be dropped onto a playlist thumbnail area, converted to PNG, and displayed without the Qt image-read error.