Ensure DM rooms have the same color in timeline and left panel.

src/domain/session/rightpanel/RoomDetailsViewModel.js

@@ -34,7 +34,7 @@ export class RoomDetailsViewModel extends ViewModel {
     }
 
     get avatarColorNumber() {
-        return getIdentifierColorNumber(this.roomId)
+        return getIdentifierColorNumber(this._room.avatarColorId)
     }
 
     avatarUrl(size) {

src/domain/session/room/RoomViewModel.js

@@ -119,7 +119,7 @@ export class RoomViewModel extends ViewModel {
     }
 
     get avatarColorNumber() {
-        return getIdentifierColorNumber(this._room.id)
+        return getIdentifierColorNumber(this._room.avatarColorId)
     }
 
     avatarUrl(size) {

src/matrix/room/Room.js

@@ -328,6 +328,10 @@ export class Room extends BaseRoom {
         });
     }
 
+    get avatarColorId() {
+        return this._heroes?.roomAvatarColorId || this._roomId
+    }
+
     get isUnread() {
         return this._summary.data.isUnread;
     }

src/matrix/room/members/Heroes.js

@@ -97,4 +97,13 @@ export class Heroes {
         }
         return null;
     }
+
+    get roomAvatarColorId() {
+        if (this._members.size === 1) {
+            for (const member of this._members.values()) {
+                return member.userId;
+            }
+        }
+        return null;
+    }
 }