Code quality: Removed some unused interfaces and classes (#11661)

Author: ferrariofilippo

src/Files.App/Controllers/IJson.cs

@@ -5,20 +5,11 @@ namespace Files.Shared.Helpers
 {
 	public static class PathHelpers
 	{
-		public static string GetParentDir(string path)
-		{
-			if (string.IsNullOrEmpty(path))
-				return string.Empty;
-
-			var index = path.Contains('/') ? path.LastIndexOf("/", StringComparison.Ordinal) : path.LastIndexOf("\\", StringComparison.Ordinal);
-			return path.Substring(0, index != -1 ? index : path.Length);
-		}
-
 		public static string Combine(string folder, string name)
 		{
 			if (string.IsNullOrEmpty(folder))
 				return name;
-			return folder.Contains('/') ? Path.Combine(folder, name).Replace("\\", "/") : Path.Combine(folder, name);
+			return folder.Contains('/') ? Path.Combine(folder, name).Replace('\\', '/') : Path.Combine(folder, name);
 		}
 	}
 }