[DevTools] Check in `frontend.d.ts` for react-devtools-fusebox, include in build output (#28970)

## Summary

The `react-devtools-fusebox` private package is used in the React Native
DevTools (Fusebox) frontend by checking build artifacts into RN's
[fork]([`facebookexperimental/rn-chrome-devtools-frontend`](https://github.com/facebookexperimental/rn-chrome-devtools-frontend))
of the Chrome DevTools (CDT) repo - see
https://github.com/facebookexperimental/rn-chrome-devtools-frontend/pull/22.

Currently, the CDT fork also includes a [manually written TypeScript
definition
file](https://github.com/facebookexperimental/rn-chrome-devtools-frontend/blob/1d5f8d5209ac49de97aec16732169d47bf525474/front_end/third_party/react-devtools/package/frontend.d.ts)
which describes `react-devtools-fusebox`'s API. This PR moves that file
into the React repo, next to the implementation of
`react-devtools-fusebox`, so we can update it atomically with changes to
the package.

As this is the first bit of TypeScript in this repo, the PR adds minimal
support for formatting `.d.ts` files with Prettier. It also opts out
`react-devtools-fusebox/dist/` from linting/formatting as a drive-by
fix.

For now, we'll just maintain the `.d.ts` file manually, but we could
consider leveraging
[`flow-api-translator`](https://www.npmjs.com/package/flow-api-translator)
to auto-generate it in the future.

## How did you test this change?

Build `react-devtools-fusebox`, observe that `dist/frontend.d.ts`
exists.