System Status: Add status button

[shey-v]

• Status buttons (#3326) need to be added to the component (in figma and code) when it is available.

This will allow users to add specific secondary actions and dismissible functionality into the System Status which is a key requirement for the component. Currently in Figma we've used a placeholder (using primary button) but this will need to be updated. In code, nothing has been added so it will be a matter of adding this in and then adding the relevant site examples from the Figma site doc spec here.