[Cashtab] Do not show parsed op return raw field if no input

Summary: This is already the expected behavior, but it is not working as there is a typo in which formData field to check for being blank.

Test Plan: npm test

Reviewers: #bitcoin_abc, emack

Reviewed By: #bitcoin_abc, emack

Differential Revision: https://reviews.bitcoinabc.org/D15915