Fix crash on startup due to events with nil email

[amcedwards]

Status

READY

Description

Small fix for #460: Created EKParticipant.safeURL as EKParticipant.url is not an optional. (Note: I'm brand new to Swift, so am quite open to a better way to solve this!)

Checklist

• [x] (N/A) Localized
• [x] Added to changelog:
  • [x] Changelog View
  • [x] CHANGELOG.md

Steps to Test or Reproduce

• Create a meeting request (via Outlook/O365) with an attendee that has an X500 email address.
• Review the meeting in Calendar; note yellow exclamation mark next to the attendee with an invalid address
• Launch MeetingBar

[leits]

WOW Thank you, @amcedwards!!

I spent so much time trying to fix this bug. Too much. 😓