Use the room heroes when computing a DM avatar. (#2900)

* Use room heroes for DM avatar content ID.

* Use RoomAvatar.heroes for the DM Details stack.

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

@@ -26,6 +26,7 @@ struct RoomSummaryDetails {
     let name: String
     let isDirect: Bool
     let avatarURL: URL?
+    let heroes: [UserProfileProxy]
     let lastMessage: AttributedString?
     let lastMessageFormattedTimestamp: String?
     let unreadMessagesCount: UInt
@@ -64,6 +65,7 @@ extension RoomSummaryDetails {
         name = string
         isDirect = true
         avatarURL = nil
+        heroes = []
         lastMessage = AttributedString(string)
         lastMessageFormattedTimestamp = "Now"
         unreadMessagesCount = hasUnreadMessages ? 1 : 0
@@ -78,4 +80,12 @@ extension RoomSummaryDetails {
         isMarkedUnread = false
         isFavourite = false
     }
+    
+    var avatar: RoomAvatar {
+        if isDirect, avatarURL == nil, heroes.count == 1 {
+            .heroes(heroes)
+        } else {
+            .room(id: id, name: name, avatarURL: avatarURL)
+        }
+    }
 }

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

@@ -252,6 +252,7 @@ class RoomSummaryProvider: RoomSummaryProviderProtocol {
                                          name: roomInfo.displayName ?? roomInfo.id,
                                          isDirect: roomInfo.isDirect,
                                          avatarURL: roomInfo.avatarUrl.flatMap(URL.init(string:)),
+                                         heroes: roomInfo.heroes.map(UserProfileProxy.init),
                                          lastMessage: attributedLastMessage,
                                          lastMessageFormattedTimestamp: lastMessageFormattedTimestamp,
                                          unreadMessagesCount: UInt(roomInfo.numUnreadMessages),