Glia iOS Core SDK 2.0.4

Changed

• Remove guard block from patchRequest
• Handle follow_up endReason for EngagementEndEvent
• Notify backend when engagement request was declined
• Change Signal to SignalProducer for unread message count
• Add engagement change emitter to interactor
• Update activeEngagement when new visitor state received
• Remove pause messaging functionality
• Add SwiftPhoenixClient and ReactiveSwift licenses.
• Add MIT license to xcframework
• Fix WebRTC local network usage