[dotnet] Fix nullability annotations on NodeRemoteValue (#16661)

* [dotnet] Fix nullability annotations on `NodeRemoteValue`

* [dotnet] Improve test for SharedId

Author: RenderMichael

dotnet/src/webdriver/BiDi/Script/RemoteValue.cs

@@ -252,7 +252,7 @@ public sealed record HtmlCollectionRemoteValue : RemoteValue
     public IReadOnlyList<RemoteValue>? Value { get; set; }
 }
 
-public sealed record NodeRemoteValue(string? SharedId, NodeProperties? Value) : RemoteValue, ISharedReference
+public sealed record NodeRemoteValue(string SharedId, NodeProperties? Value) : RemoteValue, ISharedReference
 {
     public Handle? Handle { get; set; }
 

dotnet/test/common/BiDi/Script/CallFunctionParameterTest.cs

@@ -18,6 +18,7 @@
 // </copyright>
 
 using NUnit.Framework;
+using System.Runtime.CompilerServices;
 using System.Threading.Tasks;
 
 namespace OpenQA.Selenium.BiDi.Script;
@@ -104,7 +105,10 @@ public async Task CanCallFunctionToGetElement()
 
         Assert.That(res, Is.Not.Null);
         Assert.That(res.AsSuccessResult(), Is.AssignableFrom<NodeRemoteValue>());
-        Assert.That((res.AsSuccessResult() as NodeRemoteValue).Value, Is.Not.Null);
+
+        var node = (NodeRemoteValue)res.AsSuccessResult();
+        Assert.That(node.Value, Is.Not.Null);
+        Assert.That(node.SharedId, Is.EqualTo(GetElementId(By.Id("consoleLog"))));
     }
 
     [Test]
@@ -219,4 +223,13 @@ public async Task CanCallFunctionInARealm()
         Assert.That(res1, Is.EqualTo(3));
         Assert.That(res2, Is.EqualTo(5));
     }
+
+    private string GetElementId(By selector)
+    {
+        var element = (WebElement)driver.FindElement(selector);
+        return ReflectElementId(element);
+
+        [UnsafeAccessor(UnsafeAccessorKind.Method, Name = "get_Id")]
+        static extern string ReflectElementId(WebElement element);
+    }
 }