This makes it so that we show open the settings UI instead of the modal
when adding an MCP server when clicking on `Add server`:

<img width="240" height="320" alt="image"
src="https://github.com/user-attachments/assets/bc5e9059-1053-45d5-8fd5-acfb7da48a35"
/>

We still show the modal when installing an extension. Since we're
hopefully replacing MCP extensions with MCP registry support soon, we
can leave it as is for now.

Release Notes:

- N/A