Remove the Obsolete marker on ProjectTracker

It's still obsolete, but adding it breaks people trying to compile
with warn as error enabled.

src/VisualStudio/Core/Def/Implementation/ProjectSystem/VisualStudioWorkspaceImpl.cs

@@ -86,7 +86,6 @@ internal VisualStudioProjectTracker GetProjectTrackerAndInitializeIfNecessary(IS
         /// A compatibility shim to ensure that F# and TypeScript continue to work after the deferred work goes in. This will be
         /// removed once they move to calling <see cref="GetProjectTrackerAndInitializeIfNecessary"/>.
         /// </summary>
-        [Obsolete("You should use " + nameof(GetProjectTrackerAndInitializeIfNecessary) + " or check through " + nameof(DeferredState))]
         internal VisualStudioProjectTracker ProjectTracker
         {
             get