chore: remove replace statement (#1334)

## Overview

removes replace statement for nmt

## Checklist

- [x] New and updated code has appropriate documentation
- [x] New and updated code has new and/or updated testing
- [x] Required CI checks are passing
- [x] Visual proof for any user facing features like CLI or
documentation updates
- [ ] Linked issues closed with keywords

go.mod

@@ -184,7 +184,6 @@ require (
 )
 
 replace (
-	github.com/celestiaorg/nmt v0.13.0 => github.com/celestiaorg/nmt v0.12.0
 	github.com/cosmos/cosmos-sdk => github.com/celestiaorg/cosmos-sdk v1.8.0-sdk-0.46.7
 	github.com/gogo/protobuf => github.com/regen-network/protobuf v1.3.3-alpha.regen.1
 	github.com/tendermint/tendermint => github.com/celestiaorg/celestia-core v1.14.0-tm-v0.34.23