dkg: use slices.Contains to simplify code (#4201)

There is a [new function](https://pkg.go.dev/[email protected]#Contains) added in the go1.21 standard library, which can make the code more concise and easy to read.

category: refactor
ticket: none

Author: boqishan

dkg/pedersen/reshare.go

@@ -29,10 +29,8 @@ func RunReshareDKG(ctx context.Context, config *Config, board *Board, shares []s
 
 	// Validate that AddedPeers and RemovedPeers are disjoint sets
 	for _, addedPeer := range config.Reshare.AddedPeers {
-		for _, removedPeer := range config.Reshare.RemovedPeers {
-			if addedPeer == removedPeer {
-				return nil, errors.New("peer cannot be both added and removed", z.Any("peer_id", addedPeer))
-			}
+		if slices.Contains(config.Reshare.RemovedPeers, addedPeer) {
+			return nil, errors.New("peer cannot be both added and removed", z.Any("peer_id", addedPeer))
 		}
 	}