fix: Invite and InviteMetadata properties (#1639)

* fixes #1495

* keep obsolete properties and return types for compatibility

* missing properties for SocketInvite

* Restore xml docs and change obsolete message

Co-authored-by: Paulo <pnmanjos@hotmail.com>

src/Discord.Net.WebSocket/Entities/Invites/SocketInvite.cs

@@ -49,6 +49,7 @@ namespace Discord.WebSocket
         /// <inheritdoc />
         int? IInvite.MemberCount => throw new NotImplementedException();
         /// <inheritdoc />
+        [Obsolete("This property doesn't exist anymore and shouldn't be used.")]
         bool IInviteMetadata.IsRevoked => throw new NotImplementedException();
         /// <inheritdoc />
         public bool IsTemporary { get; private set; }
@@ -138,6 +139,8 @@ namespace Discord.WebSocket
         /// <inheritdoc />
         IChannel IInvite.Channel => Channel;
         /// <inheritdoc />
-        IUser IInviteMetadata.Inviter => Inviter;
+        IUser IInvite.Inviter => Inviter;
+        /// <inheritdoc />
+        IUser IInvite.TargetUser => TargetUser;
     }
 }