Text Decoration Underline is not working on master
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**Expected behavior:**

Using `styled-components/primitives` with

```
const Link = styled.Text`
  text-decoration: underline
`
```

should render text with underline

**Observed behavior:**

Throws a JSON Parse syntax error for unexpected token '}'

```
makeTextLayer@/Users/calvinchan/airswap/component-library/plugin.sketchplugin/Contents/Sketch/styleguide.js:35247:73
renderBackingLayers@/Users/calvinchan/airswap/component-library/plugin.sketchplugin/Contents/Sketch/styleguide.js:36270:43
flexToSketchJSON@/Users/calvinchan/airswap/component-library/plugin.sketchplugin/Contents/Sketch/styleguide.js:33653:51
map@[native code]
flexToSketchJSON@/Users/calvinchan/airswap/component-library/plugin.sketchplugin/Contents/Sketch/styleguide.js:33655:60
renderContents@/Users/calvinchan/airswap/component-library/plugin.sketchplugin/Contents/Sketch/styleguide.js:35326:44
map@[native code]
render@/Users/calvinchan/airswap/component-library/plugin.sketchplugin/Contents/Sketch/styleguide.js:35395:22
/Users/calvinchan/airswap/component-library/plugin.sketchplugin/Contents/Sketch/styleguide.js:78583:65
__skpm_run@/Users/calvinchan/airswap/component-library/plugin.sketchplugin/Contents/Sketch/styleguide.js:78699:17
__skpm_run@[native code]
  line: 35247,
  column: 73,
  sourceURL: '/Users/calvinchan/airswap/component-library/plugin.sketchplugin/Contents/Sketch/styleguide.js' }
```

**How to reproduce:**

Use `styled-components` example but change the dependency of `react-sketchapp` to point to master. Then add a `text-decoration: underline` attribute to any of the styeld components

**Sketch version:**

50.2

**Please attach screenshots, a zip file of your project, and/or a link to your github project**
