Don't switch to UI thread to dispose workspace context

Relates to dotnet/roslyn#51016

src/Microsoft.VisualStudio.ProjectSystem.Managed/ProjectSystem/LanguageServices/WorkspaceProjectContextProvider.cs

@@ -57,9 +57,6 @@ public async Task ReleaseProjectContextAsync(IWorkspaceProjectContextAccessor ac
         {
             Requires.NotNull(accessor, nameof(accessor));
 
-            // TODO: https://github.com/dotnet/project-system/issues/353.
-            await _threadingService.SwitchToUIThread();
-
             try
             {
                 accessor.Context.Dispose();