Predefined Screen fails to add HTTPS to the front of some ICS files

[rsalsbery]

Summary

If an ICS file is added to a Custom Screen without the HTTPS Protocol, it is automatically added by our system; however, when you add the same ICS file to the Predefined Screen, it will not do this for you. This case is being opened to add this automation to the Predefined screen.

Steps to reproduce

1. Generate an ICS file
2. Add it to the Predefined screen but remove the HTTPS protocol

Expected behavior

HTTPS should be added to the URL to allow it to load.

Actual behavior

URL does not add the protocol, but reports the URL as valid, causing the Calendar to fail to load with no explanation.