Room preview: Use generic data from RoomPreviewData instead of RoomPreviewData.emailInvitation

Vector/Model/Room/RoomEmailInvitation.h

@@ -22,11 +22,6 @@
  */
 @interface RoomEmailInvitation : NSObject
 
-/**
- The room in the invitation.
- */
-@property (nonatomic, readonly) NSString *roomId; // TODO
-
 /**
  The invitation parameters.
  Can be nil.

Vector/Model/Room/RoomPreviewData.m

@@ -35,6 +35,10 @@
     if (self)
     {
         _emailInvitation = [[RoomEmailInvitation alloc] initWithParams:emailInvitationParams];
+
+        // Report decoded data
+        _roomName = _emailInvitation.roomName;
+        _roomAvatarUrl = _emailInvitation.roomAvatarUrl;
     }
     return self;
 }