Work Items should add to contribution graph

Creating a work item shows an entry in the activity feed but does not count as a contribution in the Contribution Graph the way opening an issue does.

To reproduce

• Sign-in if you haven't already, view your profile and the number of contributions today
• Create a bunch of tasks in an issue
• View your profile https://gdk.test:3443/yourusername
• The graph should have increased by the number of tasks