sp-dropdown has become sp-picker in Spectrum Web Components

[undavide]

Issue in /src/pages/uxp/reference-spectrum/User Interface/sp-dropdown.md

The link just below the screenshot: https://opensource.adobe.com/spectrum-web-components/components/dropdown

is broken since Spectrum Web Components have renamed the <sp-dropdown> into <sp-picker>

[ashryanbeats]

Via Kerri, for the future, the best fix is either to:

• Ask Spectrum to version their docs
• Pull the relevant Spectrum docs into our docs

Both are larger projects.

For the time being, we'll manually fix the link.