Subscribing to calendars will not work if the user does not have a calendar created

Issue Summary

When Confluence is integrated with Team Calendars, users have the option to Subscribe to Team Calendars from third-party calendars.

If a user tries to subscribe to a calendar in a space, but did not create any calendars within any Confluence space, an "Error fetching subscribe URL" message will be displayed:

Steps to Reproduce

1. Have "User A" going to a space and selecting the Calendars option from the sidebar
2. There, the user must tap the + icon at the Calendars sidebar and then, Add new calendar
3. Have "User B" going to the space where the calendar was created and select Calendars from the sidebar as well.
4. Now, this user must tap the ellipsis button at the right side of the title of the created calendar and then, Subscribe
5. Under the Calendar app field, tap the dropdown and select any option

Expected Results

The user should see the steps and URL to be copied so then it could be pasted into the third-party calendar.

Actual Results

An error message is displayed:

Workaround

• Have the user creating a test calendar in a separate space (a personal space, for example) so the subscribe option will work.
• Have the user watching a calendar (Tap the ellipsis button on a calendar > Watch) which will allow the function to work.