the native window can not resize when decorations false, resizable true

when hide the titlebar of native window, the "resizable" option is not work.

let ops = eframe::NativeOptions {
default_theme: Theme::Dark,
viewport: egui::ViewportBuilder {
decorations: Some(true),
// titlebar_shown: Some(false),
resizable: Some(true),
..Default::default()
},
..Default::default()
};

eframe::run_native(title, ops, ...);

Start by reproducing the issue with eframe::NativeOptions and egui::ViewportBuilder using decorations disabled and resizable enabled. Trace the native window handling behind eframe::run_native across the affected platform behavior, then verify that the window can be resized without decorations.

Written by the indexing model from the issue text.