Improve re-rendering of transaction{id} subscribers after a marchant change

Author: OlGierd03

src/pages/iou/request/step/IOURequestStepMerchant.tsx

@@ -124,7 +124,9 @@ function IOURequestStepMerchant({
             shouldNavigateAfterSaveRef.current = true;
             return;
         }
-        setMoneyRequestMerchant(transactionID, newMerchant || CONST.TRANSACTION.PARTIAL_TRANSACTION_MERCHANT, !isEditing, hasReceipt(transaction));
+        // updateMoneyRequestMerchant's optimisticData already sets merchant on TRANSACTION{id},
+        // also calling setMoneyRequestMerchant would trigger a redundant Onyx commit and
+        // re-render every subscriber of that key for nothing.
         if (isEditing) {
             updateMoneyRequestMerchant({
                 transactionID,
@@ -139,6 +141,8 @@ function IOURequestStepMerchant({
                 isASAPSubmitBetaEnabled,
                 parentReportNextStep,
             });
+        } else {
+            setMoneyRequestMerchant(transactionID, newMerchant || CONST.TRANSACTION.PARTIAL_TRANSACTION_MERCHANT, true, hasReceipt(transaction));
         }
         setIsSaved(true);
         shouldNavigateAfterSaveRef.current = true;