Align area charts to line and column charts

As we've added column and line charts, we introduced some changes to the chart design that need to be reflected back into the area chart component.

• With the column charts, we removed the pin line that drops from the popover to the x-axis. Thinking we should probably do that on all the charts for consistency.

• With the line charts, we made the line 2px rather than 1px. Thinking this should also be updated so that the presentation is consistent.