fix: reduce bundle size even more

Author: khawarizmus

polyfill/lib/calendar.mjs

@@ -1323,12 +1323,10 @@ const helperIslamic = ObjectAssign({}, nonIsoHelperBase, {
   DAYS_PER_ISO_YEAR: 365.2425,
   constantEra: 'ah',
   reviseIntlEra(calendarDate /*, isoDate*/) {
-    let { era, eraYear } = calendarDate;
     // Chrome for Android as of v 142.0.6367.179 mishandled the era option in Intl.DateTimeFormat
     // and returned 'bc' instead of 'ah'. This code corrects that and any possible future errors.
     // see https://issues.chromium.org/issues/40856332
-    era = 'ah';
-    return { era, eraYear };
+    return { ...calendarDate, era: 'ah' };
   },
   estimateIsoDate(calendarDate) {
     const { year } = this.adjustCalendarDate(calendarDate);