05-29: Edit completed tasks

Users can now save progress when completing their step and edit tasks once they have been completed. This helps users feel confident while completing tasks knowing that they can always go back and make changes and edit before completing and submitting their step.

1. The “Mark as complete” call to action is now much more discoverable to users. (This can be un-checked if pressed by default).
2. Users can click ‘save and close’ and come back to complete there tasks at a later date.