fix(calendar): add null check for connectedAccount in blocklist delete job

https://sonarly.com/issue/34944?type=bug

The BlocklistItemDeleteCalendarEventsJob crashes with a TypeError when a calendar channel's connectedAccount relation resolves to null, preventing blocklist-triggered calendar event cleanup from completing.

Fix: Added null-safe access to `calendarChannel.connectedAccount` using optional chaining (`?.`) and the existing `isDefined()` utility, matching the exact pattern already used in the equivalent messaging blocklist job (`messaging-blocklist-item-delete-messages.job.ts`).

The fix replaces the unsafe direct property access:
```typescript
if (calendarChannel.connectedAccount.handleAliases) {
```

With the null-safe pattern:
```typescript
const handleAliases = calendarChannel.connectedAccount?.handleAliases;
if (isDefined(handleAliases)) {
```

This prevents the TypeError when `connectedAccount` is null (due to deleted connected accounts or incomplete data migration from workspace schemas to the core metadata schema). When `connectedAccount` is null, the code now safely skips alias processing and proceeds with only the calendar channel's own handle for the blocklist matching.

packages/twenty-server/src/modules/calendar/blocklist-manager/jobs/blocklist-item-delete-calendar-events.job.ts

@@ -133,13 +133,13 @@ export class BlocklistItemDeleteCalendarEventsJob {
         for (const calendarChannel of calendarChannels) {
           const calendarChannelHandles = [calendarChannel.handle];
 
-          if (calendarChannel.connectedAccount.handleAliases) {
-            const rawAliases = calendarChannel.connectedAccount
-              .handleAliases as string | string[];
+          const handleAliases =
+            calendarChannel.connectedAccount?.handleAliases;
 
-            const aliasList = Array.isArray(rawAliases)
-              ? rawAliases
-              : rawAliases.split(',').map((alias: string) => alias.trim());
+          if (isDefined(handleAliases)) {
+            const aliasList: string[] = Array.isArray(handleAliases)
+              ? handleAliases
+              : (handleAliases as string).split(',').map((alias) => alias.trim());
 
             calendarChannelHandles.push(...aliasList);
           }