Loosen duration metric assertion

Author: anuraaga

instrumentation/opentelemetry-instrumentation-starlette/tests/test_starlette_instrumentation.py

@@ -230,7 +230,8 @@ def test_basic_post_request_metric_success(self):
                         dict(point.attributes), expected_duration_attributes
                     )
                     if metric.name == "http.server.duration":
-                        self.assertAlmostEqual(duration, point.sum, delta=30)
+                        self.assertGreaterEqual(point.sum, 0)
+                        self.assertGreaterEqual(duration, point.sum)
                     elif metric.name == "http.server.response.size":
                         self.assertEqual(response_size, point.sum)
                     elif metric.name == "http.server.request.size":