fix: hide embedding status tip if embedding completed (#13156)

> CLOSE AI-334

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Bug Fixes**
* Improved the responsiveness of embedding status updates in the AI chat
composer, reducing unnecessary refreshes when the status has not
changed.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/frontend/core/src/blocksuite/ai/components/ai-chat-composer/ai-chat-composer.ts

@@ -317,12 +317,11 @@ export class AIChatComposer extends SignalWatcher(
             this.embeddingCompleted = false;
             return;
           }
+          const prevCompleted = this.embeddingCompleted;
           const completed = status.embedded === status.total;
           this.embeddingCompleted = completed;
-          if (completed) {
-            this.embeddingCompleted = true;
-          } else {
-            this.embeddingCompleted = false;
+          if (prevCompleted !== completed) {
+            this.requestUpdate();
           }
         },
         signal