git: Fix add safe directory button doing nothing (#58705)

We had a nested spawn that was disguising the fact that the actual
`git_config` task was being dropped immediately instead of detached.
This only seems to cause problems in release builds due to timing
issues.

Self-Review Checklist:

- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

Release Notes:

- Fixed a bug where clicking the button to trust a git repository would
do nothing.

crates/git_ui/src/git_panel.rs

@@ -3174,7 +3174,7 @@ impl GitPanel {
     /// worktree to the `safe.directory` config, ensuring that, even if the user
     /// that's running the application is not the owner of `.git/`, it can still
     /// read the repository's contents.
-    fn add_safe_directory(&mut self, window: &mut Window, cx: &mut Context<Self>) {
+    fn add_safe_directory(&mut self, _window: &mut Window, cx: &mut Context<Self>) {
         let Some(active_repository) = &self.active_repository else {
             return;
         };
@@ -3192,12 +3192,10 @@ impl GitPanel {
                 path_arg,
             ];
 
-            cx.spawn_in(window, async move |git_panel, cx| {
-                git_panel.update(cx, |git_panel, cx| {
-                    git_panel.project.read(cx).git_config(path, args, cx)
-                })
-            })
-            .detach();
+            self.project
+                .read(cx)
+                .git_config(path, args, cx)
+                .detach_and_log_err(cx);
         }
     }