fix: ibc quota iterator (#1761)

## Description

1. uses new prefix store abstraction to deal with keys
2. fixes denom extranction

---

### Author Checklist

_All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues._

I have...

- [ ] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] added `!` to the type prefix if API or client breaking change
- [ ] added appropriate labels to the PR
- [ ] targeted the correct branch (see [PR Targeting](https://github.com/umee-network/umee/blob/main/CONTRIBUTING.md#pr-targeting))
- [ ] provided a link to the relevant issue or specification
- [ ] added a changelog entry to `CHANGELOG.md`
- [ ] included comments for [documenting Go code](https://blog.golang.org/godoc)
- [ ] updated the relevant documentation or specification
- [ ] reviewed "Files changed" and left comments if necessary
- [ ] confirmed all CI checks have passed

### Reviewers Checklist

_All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items._

I have...

- [ ] confirmed the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] confirmed all author checklist items have been addressed
- [ ] reviewed state machine logic
- [ ] reviewed API design and naming
- [ ] reviewed documentation is accurate
- [ ] reviewed tests and test coverage
- [ ] manually tested (if applicable)

x/uibc/keys.go

@@ -1,8 +1,6 @@
 package uibc
 
 import (
-	"encoding/hex"
-
 	"github.com/umee-network/umee/v4/util"
 )
 
@@ -30,7 +28,3 @@ func KeyTotalOutflows(ibcDenom string) []byte {
 	//  KeyPrefixDenomQuota| denom
 	return util.ConcatBytes(0, KeyPrefixDenomQuota, []byte(ibcDenom))
 }
-
-func DenomFromKeyTotalOutflows(key []byte) string {
-	return hex.EncodeToString(key[2:])
-}

x/uibc/quota/keeper/quota.go

@@ -6,6 +6,7 @@ import (
 	"time"
 
 	sdkmath "cosmossdk.io/math"
+	prefixsore "github.com/cosmos/cosmos-sdk/store/prefix"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 	transfertypes "github.com/cosmos/ibc-go/v5/modules/apps/transfer/types"
@@ -115,14 +116,14 @@ func (k Keeper) ResetQuota(ctx sdk.Context) error {
 		return err
 	}
 	k.SetTotalOutflowSum(ctx, zero)
-
 	store := ctx.KVStore(k.storeKey)
-	iter := sdk.KVStorePrefixIterator(store, uibc.KeyPrefixDenomQuota)
+	store = prefixsore.NewStore(store, uibc.KeyPrefixDenomQuota)
+	iter := sdk.KVStorePrefixIterator(store, nil)
 	defer iter.Close()
 	for ; iter.Valid(); iter.Next() {
-		ibcDenom := uibc.DenomFromKeyTotalOutflows(iter.Key())
-		q := uibc.Quota{IbcDenom: ibcDenom, OutflowSum: zero}
-		store.Set(uibc.KeyTotalOutflows(ibcDenom), k.cdc.MustMarshal(&q))
+		ibcDenom := iter.Key()
+		q := uibc.Quota{IbcDenom: string(ibcDenom), OutflowSum: zero}
+		store.Set(ibcDenom, k.cdc.MustMarshal(&q))
 	}
 	return nil
 }