Clipboard support is broken on Wayland

[Detegr]

Describe the bug

The clipboard is not working on Wayland. arboard supports only Wayland terminal applications, not graphical applications.

To Reproduce
Steps to reproduce the behavior:

use eframe::egui;

fn main() {
    let options = eframe::NativeOptions::default();
    eframe::run_native(
        "My egui App",
        options,
        Box::new(|_cc| Box::new(MyApp::default())),
    );
}

struct MyApp {
    s: String,
}

impl Default for MyApp {
    fn default() -> Self {
        Self { s: String::new() }
    }
}

impl eframe::App for MyApp {
    fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
        egui::CentralPanel::default().show(ctx, |ui| {
            if ui.button("copy test string to clipboard").clicked() {
                ctx.output().copied_text = "hello, world!".into();
            }
            ui.text_edit_multiline(&mut self.s);
        });
    }
}

1. Run the demo on Wayland.
2. Try clicking the button, or copying from the text box.
3. Nothing happens.

Expected behavior
Clipboard should work as expected.

Desktop (please complete the following information):

• OS: Linux, Wayland

[quietvoid]

The current clipboard was super inconsistent or not working at all for me in Wayland, using eframe.
Fix in #1613 works consistently now.

Thanks!