map.setStyle() does not preserve render of inline geojson data

Nobody has claimed this yet.

`map.setStyle()` causes the render of the inline geojson data to disappear, despite `map.getStyle().sources.[sourceId].data` showing data to be present.

I can force the render by calling `setData()`, so I do have a workaround, but it would be nice if the workaround isn't needed.

```
const style = map.getStyle()
// modify style as desired
map.setStyle(style)

// force a render of inline geojson, otherwise it just disappears
Object.keys(style.sources).forEach(sourceId => {
const { type, data } = style.sources[sourceId]
if (type === 'geojson' && typeof data !== 'string') {
map.getSource(sourceId).setData(data)
}
})
```

Reproduce the issue by applying map.setStyle() to a style containing inline GeoJSON, then inspect map.getStyle() and compare the render before and after. Verify that the inline GeoJSON remains rendered without the workaround's setData() calls, while preserving the existing source data.

Written by the indexing model from the issue text.