Move resetSplitShares after isSplitBill early-return in editing path

Split-bill edits use setDraftSplitTransaction (SPLIT_TRANSACTION_DRAFT),
so resetSplitShares should not write to ONYXKEYS.COLLECTION.TRANSACTION
for that path. The confirmation list's AmountField already handles
share recalculation for split-bill edits.

Co-authored-by: Eskalifer1 <Eskalifer1@users.noreply.github.com>

Author: MelvinBot

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

@@ -413,11 +413,6 @@ function IOURequestStepAmount({
             return;
         }
 
-        // Edits to the amount from the splits page should reset the split shares (only when the amount actually changed).
-        if (transaction?.splitShares) {
-            resetSplitShares(transaction, newAmount, selectedCurrency, false);
-        }
-
         // If currency has changed, then we get the default tax rate based on currency, otherwise we use the current tax rate selected in transaction, if we have it.
         const transactionTaxCode = getTransactionDetails(currentTransaction)?.taxCode;
         const defaultTaxCode = getDefaultTaxCode(policy, currentTransaction, selectedCurrency) ?? '';
@@ -431,6 +426,11 @@ function IOURequestStepAmount({
             return;
         }
 
+        // Reset split shares for non-split-bill edits (split-bill share recalculation is handled by the confirmation list).
+        if (transaction?.splitShares) {
+            resetSplitShares(transaction, newAmount, selectedCurrency, false);
+        }
+
         updateMoneyRequestAmountAndCurrency({
             transactionID,
             transactionThreadReport: report,