Update testing-library/user-event to latest version

[aduth]

Why: Since there are many improvements, bug fixes, and (importantly, for future reference) breaking changes.

Major release changelogs:

• https://github.com/testing-library/user-event/releases/tag/v14.0.0
• https://github.com/testing-library/user-event/releases/tag/v13.0.0

I had originally hoped to do a single pass at updating all of the @testing-library/ dependencies, but it's turning out to be a more painful upgrade than I'd anticipated, so I'll be doing it piecemeal.

Noteworthy upgrade remarks:

• Most userEvent actions are asynchronous, and usually incur a frame tick
  • The frame tick interferes with Sinon fake timers, since fake timers will pause all timeouts. Fortunately, a new built-in advanceTimers option allows the delay to increment the fake timers
• The latest version no longer includes keyCode or which in keyboard events. While these properties are technically deprecated, they are implemented in most browsers and used by many third-party libraries for improved backwards compatibility
  • This is the reason for some of the removal of some tested behaviors in PersonalKeyInput specs, since cleave.js relies on keyCode
• userEvent.upload against selfie fields is no longer possible because the user-facing behavior of selfie images is to prevent uploaded images. Previously this was not enforced by userEvent, but it is now. Instead, we fire the change event directly.
• userEvent.upload did not previously test the input's accept property. In fact, I'd previously reported this upstream. At the time, it was regarded as working as intended due to browser-allowable circumvention. Now, the default behavior checks accept. Since it is still possible to circumvent, we opt-out via applyAccept for test cases where we were intentionally testing against the circumvention behavior.
• userEvent.type now uses standard KeyboardEvent#key values (e.g. {esc} -> {Escape})
  • Pro-tip: https://keycode.info/