fix: Hotfix-bookings list breaks on unsupported timezone (#10225)

* Adds a check for supportedTimezone values

* adds timezone support check for attendees

packages/lib/date-fns/index.ts

@@ -30,6 +30,23 @@ export const formatTime = (
     : dayjs(date).format(timeFormat === 12 ? "h:mma" : "HH:mm");
 };
 
+/**
+ * Checks if a provided timeZone string is recognized as a valid timezone by dayjs.
+ * 
+ * @param {string} timeZone - The timezone string to be verified.
+ * @returns {boolean} - Returns 'true' if the provided timezone string is recognized as a valid timezone by dayjs. Otherwise, returns 'false'.
+ * 
+ */
+export const isSupportedTimeZone = (timeZone: string) => {
+  try {
+    dayjs().tz(timeZone);
+    return true;
+  } catch (error) {
+    return false;
+  }
+};
+
+
 /**
  * Returns a localized and translated date or time, based on the native
  * Intl.DateTimeFormat available to JS. Undefined values mean the browser's

packages/ui/components/popover/MeetingTimeInTimezones.tsx

@@ -5,6 +5,7 @@ import {
   isNextDayInTimezone,
   isPreviousDayInTimezone,
   sortByTimezone,
+  isSupportedTimeZone,
 } from "@calcom/lib/date-fns";
 
 import { Globe } from "../icon";
@@ -34,8 +35,12 @@ const MeetingTimeInTimezones = ({
   endTime,
 }: MeetingTimeInTimezonesProps) => {
   if (!userTimezone || !attendees.length) return null;
-
-  const attendeeTimezones = attendees.map((attendee) => attendee.timeZone);
+  
+  // If attendeeTimezone is unsupported, we fallback to host timezone. Unsupported Attendee timezone can be used due to bad API booking request in the past | backward-compatibility
+  
+  const attendeeTimezones = attendees.map((attendee) => {
+    return isSupportedTimeZone(attendee.timeZone) ? attendee.timeZone : userTimezone;
+  });
   const uniqueTimezones = [userTimezone, ...attendeeTimezones].filter(
     (value, index, self) => self.indexOf(value) === index
   );