Zulip allows the deletion of organization by administrators of a different organization

Zulip is an open-source team collaboration tool. The API for deleting an organization export is supposed to be restricted to organization administrators, but its handler failed to check that the field belongs to the same organization as the user. Therefore, an administrator of any organization was incorrectly allowed to delete an export of a different organization. This is fixed in Zulip Server 10.1.