editor: Fix panic when syncing empty selections (#39047)

Fixes ZED-1KF

Release Notes:

- Fixed commit modal panicking in specific scenario

crates/editor/src/editor.rs

@@ -3293,9 +3293,11 @@ impl Editor {
         cx: &mut Context<Self>,
     ) -> gpui::Subscription {
         let other_selections = other.read(cx).selections.disjoint_anchors().to_vec();
-        self.selections.change_with(cx, |selections| {
-            selections.select_anchors(other_selections);
-        });
+        if !other_selections.is_empty() {
+            self.selections.change_with(cx, |selections| {
+                selections.select_anchors(other_selections);
+            });
+        }
 
         let other_subscription = cx.subscribe(&other, |this, other, other_evt, cx| {
             if let EditorEvent::SelectionsChanged { local: true } = other_evt {