ExplicitAttribute no longer works in v0.50.0

```cs
class Test1
{
    [Test]
    public Task TestMethod()
    {
        return Task.CompletedTask;
    }

    [Test, Explicit]
    public Task TestMethod2()
    {
        throw new NotImplementedException();
    }
}
```

This used to work in 0.25.21.
Now, tests are executed even if they have the explicit attribute.