zcash_client_sqlite: Fix incorrect input selection filtering when sen…

…ding to transparent.

The "avoid pool crossing" conditions in not selection were erroneously
not taking into account the need to pay transparent outputs.

zcash_client_backend/src/data_api/wallet/input_selection.rs

@@ -403,11 +403,13 @@ where
             #[cfg(not(feature = "orchard"))]
             let orchard_input_total = NonNegativeAmount::ZERO;
 
-            let use_sapling =
-                !(sapling_outputs.is_empty() && orchard_input_total >= amount_required);
+            // Use Sapling inputs if there are no Orchard outputs or there are not sufficient
+            // Orchard outputs to cover the amount required.
+            let use_sapling = orchard_outputs.is_empty() || amount_required > orchard_input_total;
+            // Use Orchard inputs if there are insufficient Sapling funds to cover the amount
+            // reqiuired.
             #[cfg(feature = "orchard")]
-            let use_orchard =
-                !(orchard_outputs.is_empty() && sapling_input_total >= amount_required);
+            let use_orchard = amount_required > sapling_input_total;
 
             let sapling_inputs = if use_sapling {
                 shielded_inputs