Add missing attribute (#10311)

Integration tests all failed with a MEF composition error

Author: DustinCampbell

src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/Logging/RazorActivityLog.cs

@@ -26,6 +26,7 @@ private enum EntryType { Error, Warning, Info }
     private readonly AsyncBatchingWorkQueue<(EntryType, string)> _loggingQueue;
     private IVsActivityLog? _vsActivityLog;
 
+    [ImportingConstructor]
     public RazorActivityLog(
         [Import(typeof(SAsyncServiceProvider))] IAsyncServiceProvider serviceProvider,
         JoinableTaskContext joinableTaskContext)