[feature request] notification unique flag of current notification

### Existing Component
是

### Component Name
Notification

### Description
Notification通知 进行相同的多次提醒的前提下，在未关闭前，如二次提醒，是否可以直接更新提醒内容，而不新建一个通知，

Start by locating the Notification component and reading how repeated notifications are created and dismissed. Verify the desired behavior for a second identical notification while the first remains open, then confirm that the existing notification is updated rather than another one being created.

Written by the indexing model from the issue text.