test(log4net): Run the configuration binding tests against log4net 3 (#5651)

The V3 test project links the other test files added in #5592, but not
SentryAppenderConfigurationBindingTests. That file didn't compile against log4net 3, which
marks the XmlElement parameter of XmlConfigurator.Configure as non-nullable. With a
null-forgiving operator on DocumentElement it compiles, so the V3 project now links it and the
Dsn tombstone behavior is pinned on both log4net versions.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

Author: ric-oliv

test/Sentry.Log4Net.Tests/SentryAppenderConfigurationBindingTests.cs

@@ -39,7 +39,7 @@ void OnLogReceived(object? sender, LogReceivedEventArgs e)
         try
         {
             var repository = LogManager.CreateRepository(Guid.NewGuid().ToString());
-            var exception = Record.Exception(() => XmlConfigurator.Configure(repository, document.DocumentElement));
+            var exception = Record.Exception(() => XmlConfigurator.Configure(repository, document.DocumentElement!));
             return (exception, repository.GetAppenders().Length, string.Join(" | ", errors));
         }
         finally

test/Sentry.Log4Net.V3.Tests/Sentry.Log4Net.V3.Tests.csproj

@@ -12,6 +12,7 @@
       <DependentUpon>SentryAppenderTests.cs</DependentUpon>
     </Compile>
     <Compile Include="..\Sentry.Log4Net.Tests\SentryAppenderUninitializedSdkTests.cs" Link="SentryAppenderUninitializedSdkTests.cs" />
+    <Compile Include="..\Sentry.Log4Net.Tests\SentryAppenderConfigurationBindingTests.cs" Link="SentryAppenderConfigurationBindingTests.cs" />
   </ItemGroup>
 
   <ItemGroup>