style: use "text-button-icon" token for dropdown icons on Vue nodes (#6284)

## Summary

Change these dropdown icons to match [the
design](https://www.figma.com/design/31uH3r4x3xbIctuRWYW6NM/V3---Vue-Nodes?node-id=6189-6820&m=dev).

**Before**

<img width="692" height="694" alt="Selection_2196"
src="https://github.com/user-attachments/assets/aa1fb135-0ad0-4ab6-8c79-7163349b5fae"
/>

**After**

<img width="600" height="602" alt="Selection_2195"
src="https://github.com/user-attachments/assets/742ddef4-4b51-48ba-98a0-9517267de0e1"
/>

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6284-style-use-text-button-icon-token-for-dropdown-icons-on-Vue-nodes-2976d73d365081d29d2aee51e836caaf)
by [Unito](https://www.unito.io)

---------

Co-authored-by: github-actions <[email protected]>

Author: christian-byrne