Introduce a new ToggleGraphicsProfiler command (#7607)

On macOS, this will enable or disable the Metal HUD at runtime. Note
that this only works when Zed is bundled because it requires to set the
`MetalHudEnabled` key in the Info.plist.

Release Notes:

- Added a new `ToggleGraphicsProfiler` command that can be used as an
action (or via the `Help -> Toggle Graphics Profiler` menu) to
investigate graphics performance.

crates/gpui/src/platform.rs

@@ -182,8 +182,8 @@ pub(crate) trait PlatformWindow: HasWindowHandle + HasDisplayHandle {
     fn on_appearance_changed(&self, callback: Box<dyn FnMut()>);
     fn is_topmost_for_position(&self, position: Point<Pixels>) -> bool;
     fn draw(&self, scene: &Scene);
-
     fn sprite_atlas(&self) -> Arc<dyn PlatformAtlas>;
+    fn set_graphics_profiler_enabled(&self, enabled: bool);
 
     #[cfg(any(test, feature = "test-support"))]
     fn as_test(&mut self) -> Option<&mut TestWindow> {