Fix double read panic in nav history (#22754)

This one seems to be triggered when the assistant's
`View<ContextEditor>` is leased during the call into
`NavHistory::for_each_entry`, which then tries to read it again through
the `ItemHandle` interface. Fix it by skipping entries that can't be
read in the history iteration.

Release Notes:

- N/A

crates/workspace/src/pane.rs

@@ -3095,8 +3095,14 @@ impl Render for Pane {
 
 impl ItemNavHistory {
     pub fn push<D: 'static + Send + Any>(&mut self, data: Option<D>, cx: &mut WindowContext) {
-        self.history
-            .push(data, self.item.clone(), self.is_preview, cx);
+        if self
+            .item
+            .upgrade()
+            .is_some_and(|item| item.include_in_nav_history())
+        {
+            self.history
+                .push(data, self.item.clone(), self.is_preview, cx);
+        }
     }
 
     pub fn pop_backward(&mut self, cx: &mut WindowContext) -> Option<NavigationEntry> {