Default inquiry respond doesn't populate response payload #809

This issue is seen on StackStorm 3.2.0 and 3.3.0dev.

Steps to reproduce:

1. Run action core.ask and take the default parameters
2. In the Inquiries tab, go the pending inquiry and hit Respond without clicking on the "continue" checkbox
3. Expected outcome - should send default value of continue: false, but it sends into st2 api a response payload of {}
   

NB. If you instead click and then unclick the continue box, then it will send a response payload of { continue: false}

It also fails if after clicking the continue checkbox that you then click the button to return to defaults. In this scenario it again sends the response payload of {}