paymentsdb: remove dead inflight helper code

diff --git a/payments/db/sql_store.go b/payments/db/sql_store.go
index ed12a57..6454ab4 100644
--- a/payments/db/sql_store.go
+++ b/payments/db/sql_store.go
@@ -181,88 +181,6 @@ func fetchPaymentWithCompleteData(ctx context.Context,
 	return buildPaymentFromBatchData(dbPayment, batchData, true)
 }
 
-// paymentsCompleteData holds the full payment data when batch loading base
-// payment data and all the related data for a payment.
-type paymentsCompleteData struct {
-	*paymentsBaseData
-	*paymentsDetailsData
-}
-
-// batchLoadPayments loads the full payment data for a batch of payment IDs.
-func batchLoadPayments(ctx context.Context, cfg *sqldb.QueryConfig,
-	db SQLQueries, paymentIDs []int64) (*paymentsCompleteData, error) {
-
-	baseData, err := batchLoadpaymentsBaseData(ctx, cfg, db, paymentIDs)
-	if err != nil {
-		return nil, fmt.Errorf("failed to load payment base data: %w",
-			err)
-	}
-
-	batchData, err := batchLoadPaymentDetailsData(
-		ctx, cfg, db, paymentIDs, true,
-	)
-	if err != nil {
-		return nil, fmt.Errorf("failed to load payment batch data: %w",
-			err)
-	}
-
-	return &paymentsCompleteData{
-		paymentsBaseData:    baseData,
-		paymentsDetailsData: batchData,
-	}, nil
-}
-
-// paymentsBaseData holds the base payment and intent data for a batch of
-// payments.
-type paymentsBaseData struct {
-	// paymentsAndIntents maps payment ID to its payment and intent data.
-	paymentsAndIntents map[int64]sqlc.PaymentAndIntent
-}
-
-// batchLoadpaymentsBaseData loads the base payment and payment intent data for
-// a batch of payment IDs. This complements loadPaymentsBatchData which loads
-// related data (attempts, hops, custom records) but not the payment table
-// and payment intent table data.
-func batchLoadpaymentsBaseData(ctx context.Context,
-	cfg *sqldb.QueryConfig, db SQLQueries,
-	paymentIDs []int64) (*paymentsBaseData, error) {
-
-	baseData := &paymentsBaseData{
-		paymentsAndIntents: make(map[int64]sqlc.PaymentAndIntent),
-	}
-
-	if len(paymentIDs) == 0 {
-		return baseData, nil
-	}
-
-	err := sqldb.ExecuteBatchQuery(
-		ctx, cfg, paymentIDs,
-		func(id int64) int64 { return id },
-		func(ctx context.Context, ids []int64) (
-			[]sqlc.FetchPaymentsByIDsRow, error) {
-
-			records, err := db.FetchPaymentsByIDs(
-				ctx, ids,
-			)
-
-			return records, err
-		},
-		func(ctx context.Context,
-			payment sqlc.FetchPaymentsByIDsRow) error {
-
-			baseData.paymentsAndIntents[payment.ID] = payment
-
-			return nil
-		},
-	)
-	if err != nil {
-		return nil, fmt.Errorf("failed to fetch payment base "+
-			"data: %w", err)
-	}
-
-	return baseData, nil
-}
-
 // paymentsRelatedData holds all the batch-loaded data for multiple payments.
 // This does not include the base payment and intent data which is fetched
 // separately. It includes the additional data like attempts, hops, hop custom