.Net: Enable CreateFromType/Object to work with closed generics

[stephentoub]

https://github.com/microsoft/semantic-kernel/pull/6206#issuecomment-2107167732

[rogerbarreto]

Suggest adding an example on how we can retrieve a generic in the Concepts\Functions\KernelMethod_Types.cs.

I may be trying the open generics here, but would be super nice if we could use that as well, without necessarily specifying the T at the class level.

public class MyPlugin
{
    [KernelFunction]
    public T GenericResult<T>(T input) => input;

    [KernelFunction]
    public Task<T> GenericResultAsync<T>(T input) => Task.FromResult(input);
}

[stephentoub]

I may be trying the open generics here, but would be super nice if we could use that as well, without necessarily specifying the T at the class level.

This won't work today (even with my change) and is more complicated.