[web] Turn LoginModal into a functional component
Summary:
This should be a noop.
(I double checked this diff a few times, but one area that I'm generally not super solid on is useRef so that might be a place to focus on during review?)
Next diffs:
- Pull most of this component out into a separate LoginForm component and use within LoginModal.
- Render LoginForm in Splash component.
Test Plan:
- Was able to log in as before.
- Tried different error scenarios (missing fields, nonexistent username, incorrect password) and ensured that I got the right error messages and the correct inputs were focused.
Reviewers: ashoat, palys-swm
Reviewed By: ashoat, palys-swm
Subscribers: Adrian, karol-bisztyga, benschac
Differential Revision: https://phabricator.ashoat.com/D3456