Remove empty DevToolsPlugin (#21328)

# Objective

Resolves #21291

## Solution

Remove the empty DevToolsPlugin

Author: dloukadakis

crates/bevy_dev_tools/src/lib.rs

@@ -8,8 +8,6 @@
 //! This crate provides additional utilities for the [Bevy game engine](https://bevy.org),
 //! focused on improving developer experience.
 
-use bevy_app::prelude::*;
-
 #[cfg(feature = "bevy_ci_testing")]
 pub mod ci_testing;
 
@@ -22,37 +20,3 @@ pub mod picking_debug;
 pub mod states;
 
 pub use easy_screenshot::*;
-
-/// Enables developer tools in an [`App`]. This plugin is added automatically with `bevy_dev_tools`
-/// feature.
-///
-/// Warning: It is not recommended to enable this in final shipped games or applications.
-/// Dev tools provide a high level of access to the internals of your application,
-/// and may interfere with ordinary use and gameplay.
-///
-/// To enable developer tools, you can either:
-///
-/// - Create a custom crate feature (e.g "`dev_mode`"), which enables the `bevy_dev_tools` feature
-///   along with any other development tools you might be using:
-///
-/// ```toml
-/// [feature]
-/// dev_mode = ["bevy/bevy_dev_tools", "other_dev_tools"]
-/// ```
-///
-/// - Use `--feature bevy/bevy_dev_tools` flag when using the `cargo run` command:
-///
-/// `cargo run --features bevy/bevy_dev_tools`
-///
-/// - Add the `bevy_dev_tools` feature to the bevy dependency in your `Cargo.toml` file:
-///
-/// `features = ["bevy_dev_tools"]`
-///
-///  Note: The third method is not recommended, as it requires you to remove the feature before
-///  creating a build for release to the public.
-#[derive(Default)]
-pub struct DevToolsPlugin;
-
-impl Plugin for DevToolsPlugin {
-    fn build(&self, _app: &mut App) {}
-}

crates/bevy_internal/src/default_plugins.rs

@@ -80,8 +80,6 @@ plugin_group! {
         bevy_gizmos:::GizmoPlugin,
         #[cfg(feature = "bevy_state")]
         bevy_state::app:::StatesPlugin,
-        #[cfg(feature = "bevy_dev_tools")]
-        bevy_dev_tools:::DevToolsPlugin,
         #[cfg(feature = "bevy_ci_testing")]
         bevy_dev_tools::ci_testing:::CiTestingPlugin,
         #[cfg(feature = "hotpatching")]