Audio Timeline Item support (#612)

* audio timeline item support

* improved the code to reduce cognitive complexity

* no need anymore for this swiftlint disabling of a rule

* pr comments

ElementX/Sources/Services/Timeline/TimelineItemContent/CustomStringConvertible.swift

@@ -53,3 +53,9 @@ extension VideoMessageContent: CustomStringConvertible {
         String(describing: Self.self)
     }
 }
+
+extension AudioMessageContent: CustomStringConvertible {
+    public var description: String {
+        String(describing: Self.self)
+    }
+}

ElementX/Sources/Services/Timeline/TimelineItemContent/MessageTimelineItem.swift

@@ -149,3 +149,16 @@ extension MessageTimelineItem where Content == MatrixRustSDK.FileMessageContent
         return .init(source: src)
     }
 }
+
+extension MatrixRustSDK.AudioMessageContent: MessageContentProtocol { }
+
+/// A timeline item that represents an `m.room.message` event with a `msgtype` of `m.audio`.
+extension MessageTimelineItem where Content == MatrixRustSDK.AudioMessageContent {
+    var source: MediaSourceProxy {
+        .init(source: content.source)
+    }
+
+    var duration: UInt64 {
+        content.info?.duration ?? 0
+    }
+}