Follow up: window.intercomSettings

[devrnt]

It seems like window.intercomSettings isn't used in SPAs, according to #481 (comment). This is confirmed by someone from Intercom. We should follow this up and check for updated documentation, so we can remove the use window.intercomSettings uses in this codebase

[devrnt]

Also note that in both boot and update the "old" window.intercomSettings are spread into the new window.intercomSettings. So by removing the use of these global settings, we should introduce our own global settings reference