Ensure menus complete initialization

We must await InitializeMenus to ensure that menus are ready.
SwitchToMainThreadAsync doesn't exit until a solution has loaded.

Author: jcansdale

src/GitHub.VisualStudio/GitHubPackage.cs

@@ -7,7 +7,6 @@
 using System.Windows;
 using GitHub.Api;
 using GitHub.Extensions;
-using GitHub.Helpers;
 using GitHub.Info;
 using GitHub.Logging;
 using GitHub.Models;
@@ -56,7 +55,8 @@ protected override async Task InitializeAsync(CancellationToken cancellationToke
 
             await GetServiceAsync(typeof(IUsageTracker));
 
-            InitializeMenus().Forget();
+            // This package might be loaded on demand so we must await initialization of menus.
+            await InitializeMenus();
         }
 
         void LogVersionInformation()
@@ -76,8 +76,6 @@ async Task InitializeMenus()
                 return;
             }
 
-            await ThreadingHelper.SwitchToMainThreadAsync();
-
             foreach (var menu in menus.Menus)
                 serviceProvider.AddCommandHandler(menu.Guid, menu.CmdId, (s, e) => menu.Activate());