Backfill data columns (#15580)

**What type of PR is this?**

Feature

**What does this PR do? Why is it needed?**

Adds data column support to backfill.

**Acknowledgements**

- [x] I have read
[CONTRIBUTING.md](https://github.com/prysmaticlabs/prysm/blob/develop/CONTRIBUTING.md).
- [x] I have included a uniquely named [changelog fragment
file](https://github.com/prysmaticlabs/prysm/blob/develop/CONTRIBUTING.md#maintaining-changelogmd).
- [x] I have added a description to this PR with sufficient context for
reviewers to understand this PR.

---------

Co-authored-by: Kasey <kasey@users.noreply.github.com>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Preston Van Loon <preston@pvl.dev>

beacon-chain/sync/pending_blocks_queue.go

@@ -297,7 +297,10 @@ func (s *Service) handleBlockProcessingError(ctx context.Context, err error, b i
 
 // getBestPeers returns the list of best peers based on finalized checkpoint epoch.
 func (s *Service) getBestPeers() []core.PeerID {
-	_, bestPeers := s.cfg.p2p.Peers().BestFinalized(maxPeerRequest, s.cfg.chain.FinalizedCheckpt().Epoch)
+	_, bestPeers := s.cfg.p2p.Peers().BestFinalized(s.cfg.chain.FinalizedCheckpt().Epoch)
+	if len(bestPeers) > maxPeerRequest {
+		bestPeers = bestPeers[:maxPeerRequest]
+	}
 	return bestPeers
 }