Feature: Support for Exit Button at Bottom of Dialog

[GG-MD]

For which plugin is the feature?

FancyDialogs

Describe your idea

Hi! I noticed that the underlying FS_MultiActionDialog class in FancySitula already supports an exitAction parameter for positioning a button at the bottom of dialogs, but this feature isn't exposed in the FancyDialogs JSON schema. Currently, in DialogImpl.java line 170, the exitAction is hardcoded to null. It would be great if we could define an exit button in JSON that appears separately at the bottom, like this:

{
  "id": "my_dialog",
  "title": "My Dialog",
  "buttons": [...],
  "exitButton": {
    "label": "Close",
    "tooltip": "Exit dialog",
    "actions": []
  }
}

This would improve UX by visually separating the exit/close action from main dialog buttons.
The exit button should support the same actions as regular buttons, so we could either close the dialog (empty actions array) or navigate back to a previous dialog using open_dialog action.
Thanks!