Moves unique style of Link component from common to local file

components/common/link.js

@@ -26,8 +26,8 @@ Link.propTypes = {
 const styles = StyleSheet.create({
   link: {
     color: Colors.purple,
+    textDecorationLine: 'underline',
     ...Typography.mainText,
-    ...Typography.underline,
   }
 })
 

styles/typography.js

@@ -41,6 +41,5 @@ export default {
   title: {
     color: Colors.purple,
     marginVertical: Spacing.large
-  },
+  }
-  underline: { textDecorationLine: 'underline' }
 }