[Bug]: Nullability of event args is ignored in generated mocks

[Kaskadee]

Description

If the generic type argument of a EventHandler<T> is nullable, the nullability is ignored in the generated mock causing the warning CS8604: Possible null reference argument for parameter 'e' in 'void EventHandler<string>.Invoke(object? sender, string e)'.

// <auto-generated/>
#nullable enable

namespace TUnit.Mocks.Generated.Sandbox
{
    public sealed class IFooMock : global::TUnit.Mocks.Mock<global::Sandbox.IFoo>, global::Sandbox.IFoo
    {
        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
        internal IFooMock(global::Sandbox.IFoo mockObject, global::TUnit.Mocks.MockEngine<global::Sandbox.IFoo> engine)
            : base(mockObject, engine) { }

        event global::System.EventHandler<string> global::Sandbox.IFoo.Something { add => Object.Something += value; remove => Object.Something -= value; } // Should be `EventHandler<string?>` instead
    }
}

Expected Behavior

The nullability of the generic type argument is correctly copied to the generated mock implementation

Actual Behavior

The nullability is ignored causing CS8604 in the generated Raise_Something of the MockImplFactory class (which correctly uses a nullable string?)

Steps to Reproduce

using TUnit.Mocks.Generated.Sandbox;

namespace Sandbox;

public interface IFoo {
    event EventHandler<string?> Something;
}

public class TestClass {
    [Test]
    public async Task SomeTest() {
        IFooMock foo = IFoo.Mock();
    }
}

TUnit Version

1.28.7-beta

.NET Version

.NET 10.0

Operating System

Windows

IDE / Test Runner

JetBrains Rider

Error Output / Stack Trace

Restore complete (1.2s)
  Sandbox net10.0 succeeded with 1 warning(s) (1.5s) → Sandbox/bin/Debug/net10.0/Sandbox.dll
    /mnt/x/Sandbox/Sandbox/obj/Debug/net10.0/TUnit.Mocks.SourceGenerator/TUnit.Mocks.SourceGenerator.MockGenerator/Sandbox_IFoo_MockImplFactory.g.cs(29,46): warning CS8604: Possible null reference argument for parameter 'e' in 'void EventHandler<string>.Invoke(object? sender, string e)'.

Build succeeded with 1 warning(s) in 3.2s

Additional Context

No response

IDE-Specific Issue?

• I've confirmed this issue occurs when running via dotnet test or dotnet run, not just in my IDE