Autoplay the next voice message if it is the next timeline item. (#6089)

ElementX/Sources/Services/MediaPlayer/MediaPlayerProviderProtocol.swift

@@ -8,6 +8,17 @@
 
 import Foundation
 
+enum SoundEffect {
+    /// A short, light blip.
+    case tink
+    
+    var fileURL: URL {
+        switch self {
+        case .tink: URL.systemSoundsDirectory.appending(component: "Tink.caf")
+        }
+    }
+}
+
 protocol MediaPlayerProviderProtocol {
     var player: AudioPlayerProtocol { get }
     
@@ -15,6 +26,10 @@ protocol MediaPlayerProviderProtocol {
     func register(audioPlayerState: AudioPlayerState)
     func unregister(audioPlayerState: AudioPlayerState)
     func detachAllStates(except exception: AudioPlayerState?) async
+    
+    /// Plays a short sound on top of whatever is already playing. It goes through the app's own
+    /// audio session, so unlike the sounds built into iOS it is heard in silent mode too.
+    func play(soundEffect: SoundEffect)
 }
 
 // sourcery: AutoMockable