Expose isSentByMe and groupStatus in all messages builders

[nicolasbraun]

Exposing those 2 attributes in the builders, allow for more customization

For example only showing Time/status for the last message of the group

            textMessageBuilder: (
                context,
                message,
                index, {
                required bool isSentByMe,
                MessageGroupStatus? groupStatus,
              }) =>
                  FlyerChatTextMessage(
                message: message,
                index: index,
                showStatus: _shouldDisplayStatus(groupStatus),
                showTime: _shouldDisplayTime(groupStatus),
              ),

Note: I choose not to remove the isSentByMe logic inside the UI package (what would require user to pass it manually in each builder)