Refactor using directives in UiaDriverTests.cs

Removed unused `G4.WebDriver.Extensions` and `System` directives.
Repositioned `G4.WebDriver.Models` directive for better organization.
Added `G4.WebDriver.Remote.Uia` directive to include new dependencies.

Author: gravity-api

src/G4.WebDriver.Tests/UiaDriverTests.cs

@@ -1,10 +1,8 @@
-using G4.WebDriver.Extensions;
-using G4.WebDriver.Models;
+using G4.WebDriver.Models;
 using G4.WebDriver.Remote.Uia;
 
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 
-using System;
 using System.IO;
 
 namespace G4.WebDriver.Tests