Show "Restore Checkpoint" only when there were changes (#27243)

Release Notes:

- N/A

---------

Co-authored-by: Agus Zubiaga <hi@aguz.me>
Co-authored-by: Bennet Bo Fenner <bennetbo@gmx.de>
Co-authored-by: Danilo Leal <daniloleal09@gmail.com>

crates/assistant2/src/message_editor.rs

@@ -12,7 +12,6 @@ use gpui::{
 };
 use language_model::LanguageModelRegistry;
 use language_model_selector::ToggleModelSelector;
-use project::Project;
 use rope::Point;
 use settings::Settings;
 use std::time::Duration;
@@ -21,7 +20,6 @@ use theme::ThemeSettings;
 use ui::{
     prelude::*, ButtonLike, KeyBinding, PlatformStyle, PopoverMenu, PopoverMenuHandle, Tooltip,
 };
-use util::ResultExt;
 use vim_mode_setting::VimModeSetting;
 use workspace::Workspace;
 
@@ -39,7 +37,6 @@ pub struct MessageEditor {
     editor: Entity<Editor>,
     #[allow(dead_code)]
     workspace: WeakEntity<Workspace>,
-    project: Entity<Project>,
     context_store: Entity<ContextStore>,
     context_strip: Entity<ContextStrip>,
     context_picker_menu_handle: PopoverMenuHandle<ContextPicker>,
@@ -110,7 +107,6 @@ impl MessageEditor {
 
         Self {
             editor: editor.clone(),
-            project: thread.read(cx).project().clone(),
             thread,
             workspace,
             context_store,
@@ -209,8 +205,6 @@ impl MessageEditor {
 
         let thread = self.thread.clone();
         let context_store = self.context_store.clone();
-        let git_store = self.project.read(cx).git_store();
-        let checkpoint = git_store.read(cx).checkpoint(cx);
         cx.spawn(async move |_, cx| {
             refresh_task.await;
             let (system_prompt_context, load_error) = system_prompt_context_task.await;
@@ -222,11 +216,10 @@ impl MessageEditor {
                     }
                 })
                 .ok();
-            let checkpoint = checkpoint.await.log_err();
             thread
                 .update(cx, |thread, cx| {
                     let context = context_store.read(cx).snapshot(cx).collect::<Vec<_>>();
-                    thread.insert_user_message(user_message, context, checkpoint, cx);
+                    thread.insert_user_message(user_message, context, cx);
                     thread.send_to_model(model, request_kind, cx);
                 })
                 .ok();