* Update feedback forms + add unit test; Update base mail client to take form data

* Complete test coverage for Feedback

* Code cleanup + extract string constants

* Update base mail client

* Correctly propagate MailClient failures + inform user in the UI

* Revert change of a error level

* Lint + Text fixes

* Cleanup Feedback tests, update Feedback close icon + add docstring for send_email

* Renamed incorrect reference to form_data -> optional_data

* Move style for close button to _buttons_default