Correct ChatMode value

[LossyDragon]

Description

ChatMode.NEW_STEAM_CHAT's value is actually 2 to utilize the new unified chat features.

Current Work around is to send a protobuf to steam to enable this feature, usually during or after LoggedOnCallback callback.

 var uiMode = new ClientMsgProtobuf<SteammessagesClientserver2.CMsgClientUIMode.Builder>(
         SteammessagesClientserver2.CMsgClientUIMode.class,
         EMsg.ClientCurrentUIMode
 );
 uiMode.getBody().setChatMode(2);
 steamClient.send(uiMode);

Checklist

• Code compiles correctly
• All tests passing
• Samples run successfully
• Extended the README / documentation, if necessary