Allow intercom to be used with presence - will allow intercom to work without entering extension number

For larger organizations, it is impossible to remember everyone's extension. For transferring calls, we can simply press the button for the user we wish to transfer the call to, and with presence it will blind transfer to that user. This way we only need the name of who we are transferring to, not the extension.

However, with intercom we must know the extension. That is impossible if you have more than a few extensions. Please add the ability to simply press the intercom button, then the presence button for the user we wish to intercom and make that work.

Intercom is a pain if we need to maintain a list of extensions. Let's let the tech do the hard work for us.