Revert "PrepareProposal-VoteExtension integration (#6915)" (#7769)

This reverts commit 39ffa80ae7.

Nightly end-to-end tests are currently failing; revert temporarily so we can
debug.

types/block.go

@@ -518,8 +518,7 @@ func (h *Header) StringIndented(indent string) string {
 		indent, h.LastResultsHash,
 		indent, h.EvidenceHash,
 		indent, h.ProposerAddress,
-		indent, h.Hash(),
-	)
+		indent, h.Hash())
 }
 
 // ToProto converts Header to protobuf

types/vote.go

@@ -326,18 +326,6 @@ func (vote *Vote) ToProto() *tmproto.Vote {
 	}
 }
 
-func VotesToProto(votes []*Vote) (res []*tmproto.Vote) {
-	if votes == nil {
-		return nil
-	}
-
-	res = make([]*tmproto.Vote, len(votes))
-	for i, vote := range votes {
-		res[i] = vote.ToProto()
-	}
-	return
-}
-
 func VoteExtensionFromProto(pext *tmproto.VoteExtension) VoteExtension {
 	ext := VoteExtension{}
 	if pext != nil {

types/vote_set.go

@@ -226,10 +226,6 @@ func (voteSet *VoteSet) getVote(valIndex int32, blockKey string) (vote *Vote, ok
 	return nil, false
 }
 
-func (voteSet *VoteSet) GetVotes() []*Vote {
-	return voteSet.votes
-}
-
 // Assumes signature is valid.
 // If conflicting vote exists, returns it.
 func (voteSet *VoteSet) addVerifiedVote(