Add optional chaining for attendees map

Author: JakubKorytko

src/hooks/useReportAvatarDetails.ts

@@ -258,7 +258,7 @@ function useReportAvatarDetails({iouReport, report, action, ...rest}: AvatarDeta
     const attendeesIDs = transactions
         // If the transaction is a split, then attendees are not present as a property so we need to use a helper function.
         ?.flatMap<number | undefined>((tr) =>
-            tr.comment?.attendees?.map((att) => (tr.comment?.source === CONST.IOU.TYPE.SPLIT ? getSplitAuthor(tr, splits) : getPersonalDetailByEmail(att.email)?.accountID)),
+            tr.comment?.attendees?.map?.((att) => (tr.comment?.source === CONST.IOU.TYPE.SPLIT ? getSplitAuthor(tr, splits) : getPersonalDetailByEmail(att.email)?.accountID)),
         )
         .filter((accountID) => !!accountID);