[dotnet][bidi] Remove AsBiDiContextAsync helper to avoid disposal issue (#15279)

Remove AsBiDiContextAsync helper

Author: nvborisenko

dotnet/src/webdriver/BiDi/WebDriver.Extensions.cs

@@ -17,7 +17,6 @@
 // under the License.
 // </copyright>
 
-using OpenQA.Selenium.BiDi.Modules.BrowsingContext;
 using System;
 using System.Threading.Tasks;
 
@@ -44,13 +43,4 @@ public static async Task<BiDi> AsBiDiAsync(this IWebDriver webDriver)
 
         return bidi;
     }
-
-    public static async Task<BrowsingContext> AsBiDiContextAsync(this IWebDriver webDriver)
-    {
-        var bidi = await webDriver.AsBiDiAsync();
-
-        var currentBrowsingContext = new BrowsingContext(bidi, webDriver.CurrentWindowHandle);
-
-        return currentBrowsingContext;
-    }
 }

dotnet/test/common/BiDi/BiDiFixture.cs

@@ -44,8 +44,9 @@ public async Task BiDiSetUp()
 
         driver = EnvironmentManager.Instance.CreateDriverInstance(options);
 
-        context = await driver.AsBiDiContextAsync();
-        bidi = context.BiDi;
+        bidi = await driver.AsBiDiAsync();
+
+        context = (await bidi.BrowsingContext.GetTreeAsync())[0].Context;
     }
 
     [TearDown]