params: remove blockTimeIota (#5987)

## Description

- removes blocktimeiota 
- merges block params in abci and core state
- spec change: https://github.com/tendermint/spec/pull/248


Closes: #5939

test/maverick/consensus/replay.go

@@ -308,12 +308,12 @@ func (h *Handshaker) ReplayBlocks(
 		}
 		validatorSet := types.NewValidatorSet(validators)
 		nextVals := types.TM2PB.ValidatorUpdates(validatorSet)
-		csParams := types.TM2PB.ConsensusParams(h.genDoc.ConsensusParams)
+		pbParams := h.genDoc.ConsensusParams.ToProto()
 		req := abci.RequestInitChain{
 			Time:            h.genDoc.GenesisTime,
 			ChainId:         h.genDoc.ChainID,
 			InitialHeight:   h.genDoc.InitialHeight,
-			ConsensusParams: csParams,
+			ConsensusParams: &pbParams,
 			Validators:      nextVals,
 			AppStateBytes:   h.genDoc.AppState,
 		}

test/maverick/consensus/state.go

@@ -1826,7 +1826,7 @@ func (cs *State) voteTime() time.Time {
 	minVoteTime := now
 	// TODO: We should remove next line in case we don't vote for v in case cs.ProposalBlock == nil,
 	// even if cs.LockedBlock != nil. See https://docs.tendermint.com/master/spec/.
-	timeIota := time.Duration(cs.state.ConsensusParams.Block.TimeIotaMs) * time.Millisecond
+	const timeIota = time.Millisecond
 	if cs.LockedBlock != nil {
 		// See the BFT time spec https://docs.tendermint.com/master/spec/consensus/bft-time.html
 		minVoteTime = cs.LockedBlock.Time.Add(timeIota)