Attribute ScoringProfile.FunctionAggregation as nullable (Azure#16585)

* Attribute ScoringProfile.FunctionAggregation as nullable

May resolve Azure#16570, but the issue described didn't repro. That said, based on the response from the service, the field should've been attributed as nullable.

* Resolve PR feedback

Author: heaths

sdk/search/Azure.Search.Documents/CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Fixed
 
 - Fixed issue calling `SearchIndexClient.GetIndexNames` that threw an exception ([#15590](https://github.com/Azure/azure-sdk-for-net/issues/15590))
+- Fixed issue where `ScoringProfile.FunctionAggregation` did not correctly handle null values ([#16570](https://github.com/Azure/azure-sdk-for-net/issues/16570))
 
 ### Added
 

sdk/search/Azure.Search.Documents/src/Generated/Models/ScoringProfile.Serialization.cs

@@ -104,6 +104,7 @@ directive:
   where: $.definitions.ScoringProfile
   transform: >
     $.properties.text["x-nullable"] = true;
+    $.properties.functionAggregation["x-nullable"] = true;
 ```
 
 ``` yaml

sdk/search/Azure.Search.Documents/src/autorest.md

@@ -444,5 +444,47 @@ public async Task AnalyzeText()
 
             Assert.AreEqual(new[] { "The", "quick", "brown", "fox", "jumped", "over", "the", "lazy", "dog." }, tokens.Select(t => t.Token));
         }
+
+        [Test]
+        public async Task SetScoringProfile()
+        {
+            // Testing: https://github.com/Azure/azure-sdk-for-net/issues/16570
+
+            SaveDebugRecordingsOnFailure = true;
+
+            await using SearchResources resources = SearchResources.CreateWithNoIndexes(this);
+
+            string indexName = Recording.Random.GetName();
+            string scoringProfileName = Recording.Random.GetName();
+
+            // Make sure the index, if created, is cleaned up.
+            resources.IndexName = indexName;
+
+            SearchIndex index = new SearchIndex(indexName)
+            {
+                Fields =
+                {
+                    new SimpleField("id", SearchFieldDataType.String) { IsKey = true },
+                    new SearchableField("title") { IsFilterable = true, IsSortable = false },
+                },
+                DefaultScoringProfile = scoringProfileName,
+                ScoringProfiles =
+                {
+                    new ScoringProfile(scoringProfileName)
+                    {
+                        TextWeights = new TextWeights(new Dictionary<string, double>
+                        {
+                            { "title", 2 },
+                        }),
+                    },
+                },
+            };
+
+            SearchIndexClient client = resources.GetIndexClient();
+            SearchIndex createdIndex = await client.CreateIndexAsync(index);
+
+            Assert.AreEqual(1, createdIndex.ScoringProfiles.Count);
+            Assert.AreEqual(scoringProfileName, createdIndex.ScoringProfiles[0].Name);
+        }
     }
 }