Upgrade TypeScript to 4.7.4

There are a couple of code changes for us that are relevant:

1.The accuracy of `lib.d.ts` (DOM definitions) has improved, so we have
  to update a type in `Button.ts`. This changes the type from
  `X|undefined` to `X|null` so this is very minor.

2. TypeScript got better at understanding conditionals that will always
  return `true`, and caught a case where we were doing:

  ```
  addEventListener(e => e.key === 'Enter' && Common.Revealer.reveal(...)
  && false)
  ```

  TS errored because the `reveal()` call is a promise and therefore will
  always return true, causing the entire expression to return the final
  `false`. Returning `false` from an event listener doesn't do anything,
  so I've removed it.

DISABLE_THIRD_PARTY_CHECK=required updates to land TS upgrade

Bug: none
Change-Id: I89ab2ad730d40308da173bd7788c17daf0b4a511
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/3757623
Auto-Submit: Jack Franklin <jacktfranklin@chromium.org>
Commit-Queue: Jack Franklin <jacktfranklin@chromium.org>
Reviewed-by: Philip Pfaffe <pfaffe@chromium.org>