fix tests

Author: vaind

test/Sentry.Profiling.Tests/SamplingTransactionProfilerTests.cs

@@ -82,8 +82,8 @@ private SampleProfile CaptureAndValidate(ITransactionProfilerFactory factory)
         collectTask.Wait();
         var profileInfo = collectTask.Result;
         Assert.NotNull(profileInfo);
-        ValidateProfile(profileInfo.Profile, elapsedNanoseconds);
-        return profileInfo.Profile;
+        ValidateProfile(profileInfo.Profile as SampleProfile, elapsedNanoseconds);
+        return profileInfo.Profile as SampleProfile;
     }
 
     [Fact(Skip = "This test is flaky. TODO: rework")]