Add IVsTask related interfaces as free-threaded

Author: AArnott

src/Microsoft.VisualStudio.SDK.Analyzers.CodeFixes/build/AdditionalFiles/vs-threading.MembersRequiringMainThread.txt

@@ -21,4 +21,7 @@
 ![Microsoft.VisualStudio.Shell.Interop.SVsAppContainerProjectDeploy]
 ![Microsoft.VisualStudio.Shell.Interop.IVsTaskSchedulerService]
 ![Microsoft.VisualStudio.Shell.Interop.IVsTaskSchedulerService2]
+![Microsoft.VisualStudio.Shell.Interop.IVsTaskCompletionSource]
+![Microsoft.VisualStudio.Shell.Interop.IVsTaskBody]
+![Microsoft.VisualStudio.Shell.Interop.IVsTask]
 [Microsoft.VisualStudio.Shell.UIContext]::IsActive