Visible range fix (#212)

- System.ObjectDisposedException on GetVisibleRange
- Running StatusBar service from UI thread
## Test plan
Start VS and start editing files, check the output window for errors.
<!-- REQUIRED; info at
https://docs-legacy.sourcegraph.com/dev/background-information/testing_principles
-->

---------

Co-authored-by: Tomasz Gołębiowski <tgolebiowski@virtuslab.com>

src/Cody.VisualStudio/CodyPackage.cs

@@ -157,6 +157,8 @@ private void ReportSentryVsVersion()
                 scope.SetTag("vs", VsVersionService.DisplayVersion);
                 scope.SetTag("agent", VersionService.Agent);
             });
+
+            VsShellUtilities.ShutdownToken.Register(() => SentrySdk.ConfigureScope(s => s.SetTag("isShuttingDown", "true")));
         }
 
         private static void InitializeTrace()

src/Cody.VisualStudio/Services/DocumentsSyncService.cs

@@ -120,9 +120,19 @@ private DocumentRange GetVisibleRange(ITextView textView)
             if (ThreadHelper.CheckAccess())
             {
                 var lines = textView.TextViewLines;
-
-                firstVisiblePosition = ToDocumentPosition(lines.FirstVisibleLine.Start);
-                lastVisiblePosition = ToDocumentPosition(lines.LastVisibleLine.End);
+                if(lines != null && lines.IsValid)
+                {
+                    try
+                    {
+                        firstVisiblePosition = ToDocumentPosition(lines.FirstVisibleLine.Start);
+                        lastVisiblePosition = ToDocumentPosition(lines.LastVisibleLine.End);
+                    }
+                    catch(ObjectDisposedException)
+                    {
+                        return null;
+                    }
+                }
+                else return null;              
             }
             else return null;
 

src/Cody.VisualStudio/Services/StatusbarService.cs

@@ -13,8 +13,10 @@ public class StatusbarService : IStatusbarService
     {
         public void SetText(string text)
         {
-            ThreadHelper.JoinableTaskFactory.Run(delegate
+            ThreadHelper.JoinableTaskFactory.Run(async delegate
             {
+                await ThreadHelper.JoinableTaskFactory.SwitchToMainThreadAsync();
+
                 var statusBar = (IVsStatusbar)Package.GetGlobalService(typeof(SVsStatusbar));
                 int frozen;