test: use app constants (celestiaorg#3009)

## Overview

Refactor tests to use app constants instead of hardcoded values

## Checklist

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

app/ante/fee_checker_test.go

@@ -3,6 +3,7 @@ package ante
 import (
 	"testing"
 
+	"github.com/celestiaorg/celestia-app/pkg/appconsts"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/stretchr/testify/assert"
 )
@@ -16,31 +17,31 @@ func TestGetTxPriority(t *testing.T) {
 	}{
 		{
 			name:        "1 TIA fee large gas",
-			fee:         sdk.NewCoins(sdk.NewInt64Coin("utia", 1_000_000)),
+			fee:         sdk.NewCoins(sdk.NewInt64Coin(appconsts.BondDenom, 1_000_000)),
 			gas:         1000000,
 			expectedPri: 1000000,
 		},
 		{
 			name:        "1 utia fee small gas",
-			fee:         sdk.NewCoins(sdk.NewInt64Coin("utia", 1)),
+			fee:         sdk.NewCoins(sdk.NewInt64Coin(appconsts.BondDenom, 1)),
 			gas:         1,
 			expectedPri: 1000000,
 		},
 		{
 			name:        "2 utia fee small gas",
-			fee:         sdk.NewCoins(sdk.NewInt64Coin("utia", 2)),
+			fee:         sdk.NewCoins(sdk.NewInt64Coin(appconsts.BondDenom, 2)),
 			gas:         1,
 			expectedPri: 2000000,
 		},
 		{
 			name:        "1_000_000 TIA fee normal gas tx",
-			fee:         sdk.NewCoins(sdk.NewInt64Coin("utia", 1_000_000_000_000)),
+			fee:         sdk.NewCoins(sdk.NewInt64Coin(appconsts.BondDenom, 1_000_000_000_000)),
 			gas:         75000,
 			expectedPri: 13333333333333,
 		},
 		{
 			name:        "0.001 utia gas price",
-			fee:         sdk.NewCoins(sdk.NewInt64Coin("utia", 1_000)),
+			fee:         sdk.NewCoins(sdk.NewInt64Coin(appconsts.BondDenom, 1_000)),
 			gas:         1_000_000,
 			expectedPri: 1000,
 		},

app/ante/gov_test.go

@@ -6,6 +6,7 @@ import (
 	"github.com/celestiaorg/celestia-app/app"
 	"github.com/celestiaorg/celestia-app/app/ante"
 	"github.com/celestiaorg/celestia-app/app/encoding"
+	"github.com/celestiaorg/celestia-app/pkg/appconsts"
 	"github.com/celestiaorg/celestia-app/test/util/testfactory"
 	"github.com/celestiaorg/celestia-app/test/util/testnode"
 	"github.com/cosmos/cosmos-sdk/types"
@@ -18,7 +19,7 @@ func TestGovDecorator(t *testing.T) {
 	decorator := ante.NewGovProposalDecorator()
 	anteHandler := types.ChainAnteDecorators(decorator)
 	accounts := testfactory.GenerateAccounts(1)
-	coins := types.NewCoins(types.NewCoin("utia", types.NewInt(10)))
+	coins := types.NewCoins(types.NewCoin(appconsts.BondDenom, types.NewInt(10)))
 
 	msgSend := banktypes.NewMsgSend(
 		testnode.RandomAddress().(types.AccAddress),