This PR fixes the focus flow for the line chart. Before this PR change, we had a completely broken focus management in the line/bar chart.
Now you should be able
Go through all points with a link with the tab key
Tooltip should stick with focused points, but it shouldn't deactivate the mouse-based position for the tooltip element if the user cursor is moving.
Test plan
Go to the line chart storybook stories
Try to go through all points by keyboard tab-click
You should see that all points on the chart are accessible through keyboard navigation
You also should see that the line chart tooltip is rendered when one of the points is focused.
