refactor(store/v2): handle the error returned by batch.Close (#21789)

Co-authored-by: Marko <marko@baricevic.me>

store/v2/storage/pebbledb/db.go

@@ -203,15 +203,20 @@ func (db *Database) Get(storeKey []byte, targetVersion uint64, key []byte) ([]by
 // database in order to delete them.
 //
 // See: https://github.com/cockroachdb/cockroach/blob/33623e3ee420174a4fd3226d1284b03f0e3caaac/pkg/storage/mvcc.go#L3182
-func (db *Database) Prune(version uint64) error {
+func (db *Database) Prune(version uint64) (err error) {
 	itr, err := db.storage.NewIter(&pebble.IterOptions{LowerBound: []byte("s/k:")})
 	if err != nil {
 		return err
 	}
 	defer itr.Close()
 
 	batch := db.storage.NewBatch()
-	defer batch.Close()
+	defer func() {
+		cErr := batch.Close()
+		if err == nil {
+			err = cErr
+		}
+	}()
 
 	var (
 		batchCounter                              int
@@ -331,9 +336,14 @@ func (db *Database) ReverseIterator(storeKey []byte, version uint64, start, end
 	return newPebbleDBIterator(itr, storePrefix(storeKey), start, end, version, db.earliestVersion, true), nil
 }
 
-func (db *Database) PruneStoreKeys(storeKeys []string, version uint64) error {
+func (db *Database) PruneStoreKeys(storeKeys []string, version uint64) (err error) {
 	batch := db.storage.NewBatch()
-	defer batch.Close()
+	defer func() {
+		cErr := batch.Close()
+		if err == nil {
+			err = cErr
+		}
+	}()
 
 	for _, storeKey := range storeKeys {
 		if err := batch.Set([]byte(fmt.Sprintf("%s%s", encoding.BuildPrefixWithVersion(removedStoreKeyPrefix, version), storeKey)), []byte{}, nil); err != nil {
@@ -428,9 +438,14 @@ func getMVCCSlice(db *pebble.DB, storeKey, key []byte, version uint64) ([]byte,
 	return slices.Clone(value), err
 }
 
-func (db *Database) deleteRemovedStoreKeys(version uint64) error {
+func (db *Database) deleteRemovedStoreKeys(version uint64) (err error) {
 	batch := db.storage.NewBatch()
-	defer batch.Close()
+	defer func() {
+		cErr := batch.Close()
+		if err == nil {
+			err = cErr
+		}
+	}()
 
 	end := encoding.BuildPrefixWithVersion(removedStoreKeyPrefix, version+1)
 	storeKeyIter, err := db.storage.NewIter(&pebble.IterOptions{LowerBound: []byte(removedStoreKeyPrefix), UpperBound: end})