Blazor: add returnValue to onclose event of <dialog>

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Is your feature request related to a problem? Please describe the problem.

_No response_

### Describe the solution you'd like

Add the returnValue of a `` to the onclose event. The `close` event of the HTMLDialogElement is just a generic `Event`, so an empty `EventArgs` seems right. But the returnValue gives the developer the information which button was pressed to close the dialog.

### Additional context

If you have a button like this
`Submit`
then the dialog will be closed and the content of `value` is placed into the `returnValue` property of the dialog. But you have to read it separately from this property, it is not part of the close event. When you are in C# you have to use JS Interop to get this value.

Before `` you usually need a dialog service and a container component somewhere in the body and some JavaScript and C# to wire everything together. Nowadays you can create and control the basic functionality of a dialog using HTML only. Opening and closing works with buttons and command/commandfor attributes. On the C# side it is mostly sufficient to subscribe to the already provided events `close` and `toggle`. When toggle is repaired (#66479) only the returnValue is missing to be able to skip JS interop at all.