Better implementation of interrupt on Esc (#2111)

Use existing abstractions

codex-rs/tui/src/chatwidget.rs

@@ -624,14 +624,6 @@ impl ChatWidget<'_> {
         self.bottom_pane.on_file_search_result(query, matches);
     }
 
-    pub(crate) fn on_esc(&mut self) -> bool {
-        if self.bottom_pane.is_task_running() {
-            self.interrupt_running_task();
-            return true;
-        }
-        false
-    }
-
     /// Handle Ctrl-C key press.
     /// Returns CancellationEvent::Handled if the event was consumed by the UI, or
     /// CancellationEvent::Ignored if the caller should handle it (e.g. exit).