Update S4457: FP when func/action is async/await

[Evangelink]

Description

Rule raises FP when using Func with the async/await pattern.

Repro steps

public Task WithAsyncFunc(string s)
{
    if (s == null)
    {
        throw new ArgumentNullException(nameof(s));
    }

    Func<Task> func = async () => await Task.Delay(0);

    return func();
}