Remove now-redundant IsDotNet46 property

BepInEx.Preloader/Preloader.cs

@@ -28,8 +28,6 @@ namespace BepInEx.Preloader
 
 		public static bool IsPostUnity2017 { get; } = File.Exists(Path.Combine(Paths.ManagedPath, "UnityEngine.CoreModule.dll"));
 
-		public static bool IsDotNet46 { get; } = new Version("4.0.30319.42000") <= Environment.Version;
-
 		public static void Run()
 		{
 			try