Lookup GitHubServiceProvider via Services class

This allows the global service to be specified for unit testing and the essentials extension.

Author: jcansdale

src/GitHub.VisualStudio.UI/Views/Documents/IssueishCommentView.xaml.cs

@@ -9,7 +9,6 @@
 using GitHub.ViewModels;
 using GitHub.ViewModels.Documents;
 using GitHub.VisualStudio.UI.Helpers;
-using Microsoft.VisualStudio.Shell;
 
 namespace GitHub.VisualStudio.Views.Documents
 {
@@ -28,8 +27,7 @@ public IssueishCommentView()
 
         static IVisualStudioBrowser GetBrowser()
         {
-            var serviceProvider = (IGitHubServiceProvider)Package.GetGlobalService(typeof(IGitHubServiceProvider));
-            return serviceProvider.GetService<IVisualStudioBrowser>();
+            return Services.GitHubServiceProvider.GetService<IVisualStudioBrowser>();
         }
 
         void DoOpenOnGitHub()

src/GitHub.VisualStudio.UI/Views/PullRequestReviewCommentView.xaml.cs

@@ -6,7 +6,6 @@
 using GitHub.UI;
 using GitHub.ViewModels;
 using GitHub.VisualStudio.UI.Helpers;
-using Microsoft.VisualStudio.Shell;
 using ReactiveUI;
 
 namespace GitHub.VisualStudio.Views
@@ -31,8 +30,7 @@ public PullRequestReviewCommentView()
 
         static IVisualStudioBrowser GetBrowser()
         {
-            var serviceProvider = (IGitHubServiceProvider)Package.GetGlobalService(typeof(IGitHubServiceProvider));
-            return serviceProvider.GetService<IVisualStudioBrowser>();
+            return Services.GitHubServiceProvider.GetService<IVisualStudioBrowser>();
         }
 
         void DoOpenOnGitHub()