Fix: Surface specific payment error from backend instead of generic fallback

When a payment fails (e.g., report exceeds $20,000 reimbursement limit),
the backend sends a specific error message via Onyx. However, the client's
failureData also sets a generic "Unexpected error. Please try again later."
on the same reportAction. After Onyx deep-merges both errors,
getLatestErrorMessageField() picks whichever has the latest timestamp key.

By giving the client-side fallback error a timestamp of 0, backend errors
(with real timestamps) always take precedence. The fallback still displays
for network failures when no backend error is available.

Fixed Issues: Expensify/Expensify#610370

Co-authored-by: Lydia Barclay <lydiabarclay@users.noreply.github.com>

Author: MelvinBot

src/libs/actions/IOU/index.ts

@@ -9513,7 +9513,7 @@ function getPayMoneyRequestParams({
             key: `${ONYXKEYS.COLLECTION.REPORT_ACTIONS}${iouReport?.reportID}`,
             value: {
                 [optimisticIOUReportAction.reportActionID]: {
-                    errors: getMicroSecondOnyxErrorWithTranslationKey('iou.error.other'),
+                    errors: getMicroSecondOnyxErrorWithTranslationKey('iou.error.other', 0),
                 },
             },
         },