Updating the corner radius doesn’t update the UI properly
```
let sketch = require('sketch')
let doc = sketch.getSelectedDocument()
let selection = doc.selectedLayers.layers[0] //basic rect layer

let randomRadius = Math.round((Math.random()*100))
console.log("randomRadius: " + randomRadius)

selection.points.forEach(point => point.cornerRadius = randomRadius)

doc.sketchObject.inspectorController().reload()

console.log(selection.sketchObject.CSSAttributes())
```

![CleanShot 2020-06-07 at 11 49 37@2x](https://user-images.githubusercontent.com/4199296/84358945-c2294380-ab7c-11ea-966e-dfeba273b068.png)

There are two issues that I think are related
1. Updating a cornerRadius and running `inspectorController.reload()` doesn't update the radius slider. You can see its way too far to the right in the screenshot
2. Updating cornerRadius does not update the `CSSAttributes` of a layer


Related to this thread: https://sketchplugins.com/d/1897-cornerradius-and-border-radius
