fix: malicious test and prepare proposal (#2092)

Closes #2091

## Testing

`make test` passes locally

test/util/malicious/app_test.go

@@ -106,7 +106,8 @@ func TestMaliciousTestNode(t *testing.T) {
 	eds, err := ExtendShares(rawSquare)
 	require.NoError(t, err)
 
-	dah := da.NewDataAvailabilityHeader(eds)
+	dah, err := da.NewDataAvailabilityHeader(eds)
+	require.NoError(t, err)
 	require.Equal(t, block.Block.DataHash.Bytes(), dah.Hash())
 
 	correctSquare, err := square.Construct(block.Block.Txs.ToSliceOfBytes(), appconsts.LatestVersion, appconsts.DefaultSquareSizeUpperBound)
@@ -115,6 +116,7 @@ func TestMaliciousTestNode(t *testing.T) {
 	goodEds, err := da.ExtendShares(shares.ToBytes(correctSquare))
 	require.NoError(t, err)
 
-	goodDah := da.NewDataAvailabilityHeader(goodEds)
+	goodDah, err := da.NewDataAvailabilityHeader(goodEds)
+	require.NoError(t, err)
 	require.NotEqual(t, block.Block.DataHash.Bytes(), goodDah.Hash())
 }

test/util/malicious/out_of_order_prepare.go

@@ -56,7 +56,10 @@ func (a *App) OutOfOrderPrepareProposal(req abci.RequestPrepareProposal) abci.Re
 
 	// create the new data root by creating the data availability header (merkle
 	// roots of each row and col of the erasure data).
-	dah := da.NewDataAvailabilityHeader(eds)
+	dah, err := da.NewDataAvailabilityHeader(eds)
+	if err != nil {
+		panic(err)
+	}
 
 	// tendermint doesn't need to use any of the erasure data, as only the
 	// protobuf encoded version of the block data is gossiped.