Required fields are not identified as such on the Edit page for a webapp <https://marketplace.mozilla.org/en-US/developers/app/[NAME]/edit>. For example, the Support Information > Email field is required, but there's no indication of that (unlike on the Details page of the submission flow, where required fields are marked with red asterisks). The page does complain if you try to save changes while leaving such a field blank, but it'd be better for it to mark required fields so you don't have to get to that point to find out about them.
First of all, it is off that we require Support Email in two different places(Edit Listing and Manage Payments) Also, we don't indicate that it is a required field in Manage Payments page at https://marketplace-dev.allizom.org/en-US/developers/app/seavans-undersea-adventure-11/payments
Since we now required elsewhere, let's remove it from Manage Payments. I only added it there because it was required for payments and I felt it made sense to have it there. So it's pointless on manage payments. Let's just remove some code :)
Marked required fields on Manage Payments: https://github.com/cvan/zamboni/commit/132cc0b Filed bug 740276 to remove Support Email from Manage Payments pages.