Apply spacing to byline 'dotted line' without relying on document structure

A dotted line is displayed between the byline and notification toggle in the app layout on smaller viewports. This is rendered using the `DottedLine` component from Source Development Kitchen.

Contextual spacing is applied in `ArticleMeta.apps.tsx` via a very specific CSS selector:

```css
address > div > span > div:first-of-type {}
```

This is brittle and liable to break if the document structure changes. (This already happened when the `DottedLine` component was updated to be rendered with CSS rather than an SVG.)

We should look at applying the spacing directly to a containing element at the point where the component is used so we're not reliant on specific selectors and document structure.