[8.19] Add 3 case JSON union type matching method (#8821) (#8822)

Co-authored-by: Florian Bernd <git@flobernd.de>

Author: github-actions[bot]

src/Elastic.Clients.Elasticsearch/_Shared/Next/JsonUnionSelector.cs

@@ -77,6 +77,7 @@ public static UnionTag T2(ref Utf8JsonReader reader, JsonSerializerOptions optio
 	}
 
 	// We avoid using a `params` array for performance reasons. Create `Match()` overloads with additional parameters as needed.
+
 	public static UnionTag Match(ref Utf8JsonReader reader, JsonSerializerOptions options, JsonUnionSelectorFunc case1, JsonUnionSelectorFunc case2)
 	{
 		if (case1(ref reader, options) is var tag1 and not UnionTag.None)
@@ -92,6 +93,27 @@ public static UnionTag Match(ref Utf8JsonReader reader, JsonSerializerOptions op
 		return UnionTag.None;
 	}
 
+	public static UnionTag Match(ref Utf8JsonReader reader, JsonSerializerOptions options, JsonUnionSelectorFunc case1, JsonUnionSelectorFunc case2,
+		JsonUnionSelectorFunc case3)
+	{
+		if (case1(ref reader, options) is var tag1 and not UnionTag.None)
+		{
+			return tag1;
+		}
+
+		if (case2(ref reader, options) is var tag2 and not UnionTag.None)
+		{
+			return tag2;
+		}
+
+		if (case3(ref reader, options) is var tag3 and not UnionTag.None)
+		{
+			return tag3;
+		}
+
+		return UnionTag.None;
+	}
+
 	public static UnionTag MatchTokenTypes(ref Utf8JsonReader reader, JsonSerializerOptions options, JsonTokenTypes types, JsonUnionSelectorFunc next)
 	{
 		if (((int)types & (1 << (int)reader.TokenType)) is not 0)