Unhandled user callback exception on dynamic library interaction

**Describe the bug**
When use dynamic library to render, clicking the exit button the application stop for seconds and exit with error.

**To Reproduce**
Steps to reproduce the behavior:
**main.rs**:
```rust
use eframe::egui::{self, Context};
use eframe::{App, Frame};
use libloading::{Library, Symbol};
use std::fs;

pub struct Program {
libs: Vec,
}

impl Default for Program {
fn default() -> Program {
let plugins = fs::read_dir("libs/").expect("no plugins folder!");
let mut libs = vec![];
for plugin in plugins {
unsafe {
let path = plugin.unwrap().path();
let lib = Library::new(path).expect("couldn't find dll");
libs.push(lib);
}
}
Self { libs }
}
}

impl App for Program {
fn update(&mut self, ctx: &Context, _frame: &mut Frame) {
for lib in &self.libs {
unsafe {
let func: Symbol = lib.get(b"render").unwrap();
func(ctx);
}
}
egui::SidePanel::right("main").show(ctx, |ui| {
ui.heading("My egui Application Main");
});
}
}

fn main() {
let options = eframe::NativeOptions {
viewport: egui::ViewportBuilder::default().with_inner_size([320.0, 240.0]),
..Default::default()
};
eframe::run_native(
"My egui App",
options,
Box::new(|_cc| Ok(Box::::default())),
)
.unwrap();
}
```
**lib.rs**:
```rust
use eframe::egui;
use eframe::egui::Context;

#[no_mangle]
pub fn render(ctx: &Context) {
egui::SidePanel::left("dll").show(ctx, |ui| {
ui.heading("My egui Application dll");
});
}
```
**Expected behavior**
Exit normally.

**Screenshots**

**Desktop (please complete the following information):**
- OS: Windows11

**Additional context**
Error appears on both ``Glow`` and ``wgpu`` backend.
Both panic before dropping `painter`.
**Eframe version:** 0.28.1
Error ``0xc000041d`` exists when exception isn't handled in ``windows``' user callback.

Start with the supplied main.rs and lib.rs reproduction on Windows 11 using eframe 0.28.1, then compare the exit behavior under both the Glow and wgpu backends. Done means the application exits normally without the reported 0xc000041d exception or a panic before the painter is dropped.

Written by the indexing model from the issue text.