Remove network.protocol.name from request duration metric (#51593)

Co-authored-by: James Newton-King <james@newtonking.com>

Author: github-actions[bot]

src/Hosting/Hosting/src/Internal/HostingMetrics.cs

@@ -24,12 +24,12 @@ public HostingMetrics(IMeterFactory meterFactory)
         _activeRequestsCounter = _meter.CreateUpDownCounter<long>(
             "http.server.active_requests",
             unit: "{request}",
-            description: "Number of HTTP requests that are currently active on the server.");
+            description: "Number of active HTTP server requests.");
 
         _requestDuration = _meter.CreateHistogram<double>(
             "http.server.request.duration",
             unit: "s",
-            description: "Measures the duration of inbound HTTP requests.");
+            description: "Duration of HTTP server requests.");
     }
 
     // Note: Calling code checks whether counter is enabled.
@@ -54,7 +54,6 @@ public void RequestEnd(string protocol, bool isHttps, string scheme, string meth
 
         if (_requestDuration.Enabled)
         {
-            tags.Add("network.protocol.name", "http");
             if (TryGetHttpVersion(protocol, out var httpVersion))
             {
                 tags.Add("network.protocol.version", httpVersion);

src/Hosting/Hosting/test/HostingMetricsTests.cs

@@ -92,7 +92,6 @@ public void MultipleRequests()
         static void AssertRequestDuration(CollectedMeasurement<double> measurement, string httpVersion, int statusCode, string exceptionName = null, bool? unhandledRequest = null)
         {
             Assert.True(measurement.Value > 0);
-            Assert.Equal("http", (string)measurement.Tags["network.protocol.name"]);
             Assert.Equal(httpVersion, (string)measurement.Tags["network.protocol.version"]);
             Assert.Equal(statusCode, (int)measurement.Tags["http.response.status_code"]);
             if (exceptionName == null)