ux: [des] bug fix: fix app not working after canceling file upload

Addresses #1736 (closed)

Notes:

• For some reason, canceling the file upload via the filesystem picker triggers a change event on the input. Not sure if that's an Electron bug or a React Native web bug (it's not standard web behavior from what I've tested)
• Reproduction steps to test against can be found here: #1736 (comment 921442094)