refactor: remove Object.freeze hack in getConnectedCalendars (#27070)

* refactor: remove Object.freeze hack in getConnectedCalendars

The previous implementation used Object.freeze to prevent the destinationCalendar
object from being mutated when looping through multiple calendar credentials.
This was a workaround for a bug where the wrong calendar's primaryEmail and
integrationTitle would be set when multiple credentials existed.

This refactor properly fixes the issue by:
1. Only setting destinationCalendar once (when first found)
2. Using a flag to track when the destination calendar is found in the current credential
3. Only setting primaryEmail and integrationTitle for the credential that contains
   the destination calendar

Fixes the hack mentioned in: https://github.com/calcom/cal.com/pull/7644

Co-Authored-By: alex@cal.com <me@alexvanandel.com>

* refactor: move destinationCalendar enrichment outside the loop

Per feedback, moved the destinationCalendar finding and enrichment
completely outside the Promise.all loop. After all connected calendars
are fetched, we search through the results to find and enrich the
destination calendar with primaryEmail and integrationTitle.

Co-Authored-By: alex@cal.com <me@alexvanandel.com>

---------

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

packages/features/calendars/lib/CalendarManager.ts

@@ -54,7 +54,6 @@ export const getConnectedCalendars = async (
   selectedCalendars: { externalId: string }[],
   destinationCalendarExternalId?: string
 ) => {
-  let destinationCalendar: IntegrationCalendar | undefined;
   const connectedCalendars = await Promise.all(
     calendarCredentials.map(async (item) => {
       try {
@@ -85,7 +84,6 @@ export const getConnectedCalendars = async (
         const cals = await calendarInstance.listCalendars();
         const calendars = sortBy(
           cals.map((cal: IntegrationCalendar) => {
-            if (cal.externalId === destinationCalendarExternalId) destinationCalendar = cal;
             return {
               ...cal,
               readOnly: cal.readOnly || false,
@@ -107,12 +105,6 @@ export const getConnectedCalendars = async (
             },
           };
         }
-        // HACK https://github.com/calcom/cal.com/pull/7644/files#r1131508414
-        if (destinationCalendar && !Object.isFrozen(destinationCalendar)) {
-          destinationCalendar.primaryEmail = primary.email;
-          destinationCalendar.integrationTitle = integration.title;
-          destinationCalendar = Object.freeze(destinationCalendar);
-        }
 
         return {
           integration: safeToSendIntegration,
@@ -149,6 +141,27 @@ export const getConnectedCalendars = async (
     })
   );
 
+  let destinationCalendar: IntegrationCalendar | undefined;
+  if (destinationCalendarExternalId) {
+    for (const connectedCalendar of connectedCalendars) {
+      if (!("calendars" in connectedCalendar) || !connectedCalendar.calendars) {
+        continue;
+      }
+      const calendar = connectedCalendar.calendars.find(
+        (cal) => cal.externalId === destinationCalendarExternalId
+      );
+      if (calendar) {
+        destinationCalendar = {
+          ...calendar,
+          primary: calendar.primary ?? undefined,
+          primaryEmail: connectedCalendar.primary?.email,
+          integrationTitle: connectedCalendar.integration?.title,
+        };
+        break;
+      }
+    }
+  }
+
   return { connectedCalendars, destinationCalendar };
 };