fix(core): cannot space inside ai panel input (#12167)

### TL;DR

fix: cannot space inside ai panel input

> CLOSE BS-3428

packages/frontend/core/src/blocksuite/ai/entries/space/setup-space.ts

@@ -52,8 +52,9 @@ export function setupSpaceAIEntry(panel: AffineAIPanelWidget) {
           event.preventDefault();
           insertSpace(host);
           panel.hide();
-          return;
         }
+
+        return;
       }
 
       const selection = host.selection.find(TextSelection);