Add analytics to xpack usage (#4728) (#4753)

Relates: #4718
Added in Elasticsearch 7.8.0

Co-authored-by: Russ Cam <[email protected]>

Author: github-actions[bot]

src/Nest/XPack/Info/XPackUsage/XPackUsageResponse.cs

@@ -98,6 +98,18 @@ public class XPackUsageResponse : ResponseBase
 
 		[DataMember(Name = "enrich")]
 		public XPackUsage Enrich { get; set; }
+
+		[DataMember(Name = "spatial")]
+		public XPackUsage Spatial { get; internal set; }
+
+		[DataMember(Name = "analytics")]
+		public AnalyticsUsage Analytics { get; internal set; }
+	}
+
+	public class AnalyticsUsage : XPackUsage
+	{
+		[DataMember(Name = "stats")]
+		public IReadOnlyDictionary<string, long> Stats { get; internal set; } = EmptyReadOnly<string, long>.Dictionary;
 	}
 
 	public class SlmUsage : XPackUsage

tests/Tests/XPack/Info/XPackInfoApiTests.cs

@@ -129,6 +129,12 @@ [I] public async Task XPackUsageResponse() => await Assert<XPackUsageResponse>(X
 			{
 				r.Enrich.Should().NotBeNull();
 			}
+
+			if (TestConfiguration.Instance.InRange(">=7.8.0"))
+			{
+				r.Analytics.Should().NotBeNull();
+				r.Analytics.Stats.Should().NotBeNull().And.NotBeEmpty();
+			}
 		});
 	}
 }