remove unused usings

Author: shacharPash

tests/NRedisStack.Tests/Examples/ExamplesTests.cs

@@ -1,7 +1,4 @@
-using System.Text.Json;
-using System.Text.Json.Nodes;
 using Moq;
-using Newtonsoft.Json.Linq;
 using NRedisStack.DataTypes;
 using NRedisStack.RedisStackCommands;
 using NRedisStack.Search;