Fix: Fixed issue where custom folder icons weren't loading (#14604)

Author: yaira2

src/Files.App/Utils/Shell/Win32API.cs

@@ -280,7 +280,7 @@ public static (byte[]? icon, byte[]? overlay, bool isIconCached) GetFileIconAndO
 
 					if (getIconOnly)
 						flags |= Shell32.SIIGBF.SIIGBF_ICONONLY;
-					else
+					else if (!isFolder)
 						flags |= Shell32.SIIGBF.SIIGBF_THUMBNAILONLY;
 
 					var hres = shellFactory.GetImage(new SIZE(thumbnailSize, thumbnailSize), flags, out var hbitmap);