Horde: Optimize telemetry endpoint to handle multiple metrics

#rnx

[CL 30808982 by josh engebretson in ue5-main branch]

Engine/Source/Programs/Shared/EpicGames.Horde/Telemetry/TelemetryMessages.cs

@@ -35,6 +35,16 @@ namespace EpicGames.Horde.Telemetry
 	/// </summary>
 	public class GetTelemetryMetricsResponse
 	{
+		/// <summary>
+		/// The corresponding metric id
+		/// </summary>
+		public string MetricId { get; set; } = String.Empty;
+
+		/// <summary>
+		/// Metric grouping information
+		/// </summary>
+		public string GroupBy { get; set; } = String.Empty;
+
 		/// <summary>
 		/// Metrics matching the search terms
 		/// </summary>