perf(electron): add index for updates (#6951)

![image.png](https://graphite-user-uploaded-assets-prod.s3.amazonaws.com/T2klNLEk0wxLh4NRDzhk/cd2e982a-f78a-4cc3-b090-ee4c0090e19d.png)

Above image shows the performance on querying a 20k rows of updates table, which is super slow at 150+ms. After adding index for doc_id the performance should be greatly improved.

After:
![image.png](https://graphite-user-uploaded-assets-prod.s3.amazonaws.com/T2klNLEk0wxLh4NRDzhk/45ea4389-1833-4dc5-bd64-84d8c99cd647.png)

fix TOV-866

packages/frontend/electron/test/db/workspace-db-adapter.spec.ts

@@ -51,6 +51,6 @@ test('on destroy, check if resources have been released', async () => {
   };
   db.update$ = updateSub as any;
   await db.destroy();
-  expect(db.db).toBe(null);
+  expect(db.adapter.db).toBe(null);
   expect(updateSub.complete).toHaveBeenCalled();
 });