Fix vector-im/element-x-ios/issues/134 - Prevent home screen room last message attributed string from being computed on every update

Add async/await methods to the AttributedStringBuilder and adopt them throughout the app

ElementX/Sources/Services/Room/RoomSummary/RoomSummary.swift

@@ -46,21 +46,21 @@ class RoomSummary: RoomSummaryProtocol {
         roomProxy.isTombstoned
     }
     
+    private(set) var avatar: UIImage? {
+        didSet {
+            callbacks.send(.updatedAvatar)
+        }
+    }
+    
     private(set) var displayName: String? {
         didSet {
-            callbacks.send(.updatedData)
+            callbacks.send(.updatedDisplayName)
         }
     }
     
     private(set) var lastMessage: EventBrief? {
         didSet {
-            callbacks.send(.updatedData)
-        }
-    }
-    
-    private(set) var avatar: UIImage? {
-        didSet {
-            callbacks.send(.updatedData)
+            callbacks.send(.updatedLastMessage)
         }
     }
     

ElementX/Sources/Services/Room/RoomSummary/RoomSummaryProtocol.swift

@@ -10,7 +10,9 @@ import Combine
 import UIKit
 
 enum RoomSummaryCallback {
-    case updatedData
+    case updatedAvatar
+    case updatedDisplayName
+    case updatedLastMessage
 }
 
 @MainActor