Make `<UDropdownMenu>` searchable

### Package

v4.x

### Description

My use-case is searching sub-menu items. `DropdownMenuItem` could have a `search` type.

**Example**

<img width="443" height="400" alt="Image" src="https://github.com/user-attachments/assets/5b8e17ae-358c-4e0d-9c72-57eb457f3ee3" />

### Additional context

_No response_