feature(#22): this commit makes System.Text.Json a global using statement in the project

Author: https-richardy

Applications/Backend/Tests/Integration/Security/KeyRotationIntegrationTests.cs

@@ -1,5 +1,3 @@
-using System.Text.Json;
-
 namespace HttpsRichardy.Federation.TestSuite.Integration.Security;
 
 public sealed class KeyRotationIntegrationTests(IntegrationEnvironmentFixture factory) :

Applications/Backend/Tests/Usings.cs

@@ -1,6 +1,7 @@
 global using System.Net;
 global using System.Net.Http.Headers;
 global using System.Net.Http.Json;
+global using System.Text.Json;
 
 global using System.IdentityModel.Tokens.Jwt;
 global using System.Security.Cryptography;