Describe the bug

For PVWatts-Battery configurations, the land area value on the Installation Costs page is zero, and the $/acre costs do not update with land area.

To Reproduce

Steps to reproduce the behavior:

1. Create a default PVWatts-Battery / Commercial case.'
2. Compare the land area shown on the Installation Costs page to the value on the System Design page.

Expected behavior

All configurations that use the PVWatts System Design UI form should correctly read the land area for the Installation Costs page.