Fix Previewer crash from Refit reflection (#14282) (#14301)

src/Avalonia.DesignerSupport/DesignWindowLoader.cs

@@ -35,7 +35,7 @@ namespace Avalonia.DesignerSupport
                         new Uri($"avares://{Path.GetFileNameWithoutExtension(assemblyPath)}{xamlFileProjectPath}");
                 }
 
-                var localAsm = assemblyPath != null ? Assembly.LoadFile(Path.GetFullPath(assemblyPath)) : null;
+                var localAsm = assemblyPath != null ? Assembly.LoadFrom(Path.GetFullPath(assemblyPath)) : null;
                 var useCompiledBindings = localAsm?.GetCustomAttributes<AssemblyMetadataAttribute>()
                     .FirstOrDefault(a => a.Key == "AvaloniaUseCompiledBindingsByDefault")?.Value;
 

src/Avalonia.DesignerSupport/Remote/RemoteDesignerEntryPoint.cs

@@ -172,7 +172,7 @@ namespace Avalonia.DesignerSupport.Remote
             var transport = CreateTransport(args);
             if (transport is ITransportWithEnforcedMethod enforcedMethod)
                 args.Method = enforcedMethod.PreviewerMethod;
-            var asm = Assembly.LoadFile(System.IO.Path.GetFullPath(args.AppPath));
+            var asm = Assembly.LoadFrom(System.IO.Path.GetFullPath(args.AppPath));
             var entryPoint = asm.EntryPoint ?? throw Die($"Assembly {args.AppPath} doesn't have an entry point");
             Log($"Initializing application in design mode");
             Design.IsDesignMode = true;