Back out "[bundles] stop building legacy Paper renderer (#31429)" (#31437)

Backs out the 2 related commits:
-
https://github.com/facebook/react/commit/f8f6e1a21a1cac64cf6faf666367d641b2d8b171
-
https://github.com/facebook/react/commit/6c0f37f94b020279fb5ada70facc008fccb7172e

Since I only realized when syncing that we need the version of `react`
and the legacy renderer to match.

While I investigate if there's anything we can do to work around that
while preserving the legacy renderer, this unblocks the sync.