remove close_on_esc (bevyengine#12859)

# Objective

- Remove `close_on_esc`
- For context about why we are removing it see:
[discord](https://discordapp.com/channels/691052431525675048/692572690833473578/1225075194524073985)

## Migration Guide

- Users who added `close_on_esc` in their application will have to
replace it with their own solution.

```rust
pub fn close_on_esc(
    mut commands: Commands,
    focused_windows: Query<(Entity, &Window)>,
    input: Res<ButtonInput<KeyCode>>,
) {
    for (window, focus) in focused_windows.iter() {
        if !focus.focused {
            continue;
        }

        if input.just_pressed(KeyCode::Escape) {
            commands.entity(window).despawn();
        }
    }
}
```

crates/bevy_dev_tools/src/lib.rs

@@ -18,10 +18,6 @@ pub mod fps_overlay;
 #[cfg(feature = "bevy_ui_debug")]
 pub mod ui_debug_overlay;
 
-mod close_on_esc;
-
-pub use crate::close_on_esc::close_on_esc;
-
 /// Enables developer tools in an [`App`]. This plugin is added automatically with `bevy_dev_tools`
 /// feature.
 ///