OSRA-207 Add 'Payment Plan' to Sponsor

OSRA-207
You should be able to use Capybara to grab the HTML element in question, then test that its options include no more than one blank string. 

The `value` for an `option` that's included if `include_blank: true` is `nil`; if you explicitly include an empty string in the `collection`, it's value will be an integer - perhaps that can be useful too.