Date attributes become time-shifted when updated through Timur (only via store)

[coleshaw]

When I update a date_time attribute in the UI, the "displayed" / saved date is one day prior. I ran into a similar issue when scripting the document record updates, and I suspect this a UTC time issue / Pacific time issue, but it should only be in the Timur UI code. When you reload the page, the date returns to the entered date.

Steps to reproduce:

1. Edit a date attribute and pick a date.

2. Save the change. Note that the date that appears post-save is one day prior to the selected one.

3. Reload the page. Note that the date is what was originally selected.