Unable to use ICS CalDav URL if calendar event has jira events with JQL that returns no context

Issue Summary

If you have Team Calendars with an Jira Event that uses JQL. You'll be unable to subscribe to the ics CalDav URL provided if a single events JQL search has an invalid content (i.e. a field that doesn't exist).

Steps to Reproduce

1. Create Team Calendar
2. Add Jira Issue Event with custom JQL that attempts to load a project with an issue/event that doesn't exist
3. Grab the ics CalDav URL
4. Attempt to navigate to the URL in the browser OR attempt to set up 2 way sync through mail client.

I attached the below video to show the behavior experienced:

• Screen Recording 2022-08-12 at 1.54.23 PM.mov 

Expected Results

Should be able to subscribe to a calendar with CalDav.

Actual Results

If you navigate to the URL you'll get the below message in the Browser Network Console:

Request URL: https://ispann3.atlassian.net/wiki/rest/calendar-services/1.0/calendar/export/subcalendar/private/c98e77fc27c91eaa57c7bb0a6bdd7f234d4fbcc0.ics
Request Method: GET
Status Code: 500 
Remote Address: 104.192.140.20:443
Referrer Policy: strict-origin-when-cross-origin

If you attempt to use the CalDav URL in a mail client it'll never sync.

Workaround

There are 2 possible ways to fix this:

• Update the Calendar events to use JQL that returns valid results

OR

• Delete the event (with the broken JQL) from the calendar