[Vue node] Dropdown option isn't always on the top

Got some reports about this today. The dropdown option is covered by other nodes.

Version:

Main branch

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-6994-Vue-node-Dropdown-option-isn-t-always-on-the-top-2b86d73d3650819ea025f38ddcf49381) by [Unito](https://www.unito.io)

Start by reproducing the dropdown layering problem in the Vue node on the main branch, using the screenshots and issue description as the starting point. Inspect the frontend code responsible for rendering the dropdown and overlapping nodes; it is done when the dropdown option remains visible above other nodes in the reported cases.

Written by the indexing model from the issue text.