Fix tests

Author: shana

src/GitHub.Exports/Models/UsageModel.cs

@@ -7,7 +7,8 @@ public class UsageModel
         public DimensionsModel Dimensions { get; set; } = new DimensionsModel();
         public MeasuresModel Measures { get; set; } = new MeasuresModel();
 
-        protected UsageModel() { }
+        // this should never be called by our code but it's required to be public by the serialization code
+        public UsageModel() { }
 
         public static UsageModel Create(Guid guid)
         {

test/UnitTests/GitHub.VisualStudio/Services/MetricsTests.cs

@@ -25,7 +25,7 @@ public void ShouldStartTimer()
             var service = Substitute.For<IUsageService>();
             var target = new UsageTracker(CreateServiceProvider(), service, CreatePackageSettings());
 
-            service.Received(1).StartTimer(Arg.Any<Func<Task>>(), TimeSpan.FromMinutes(3), TimeSpan.FromHours(8));
+            service.Received(1).StartTimer(Arg.Any<Func<Task>>(), TimeSpan.FromMinutes(3), TimeSpan.FromDays(1));
         }
 
         [Test]