Are there plans to support resizable Modals?

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

Flexible reusable egui components like egui-file-dialog have a hard time to decide the right size for a Modal - it can even vary while the Modal is being used. Making it resizable would help users.

Describe the solution you'd like E.g. to configure size and resizability similar to how it is done on Viewport.

Describe alternatives you've considered

Additional context As a common example, the file-selection dialog on Mac or windows is resizable.