GFriend’s Yuju and IZ’s Jihoo have finally released their duet! The duet is for the track “Heart Signal” which shows off their youthfulness in the track and colorful music video. This comes out right when the duet for GFriend’s Eunha and Teen Top’s Chunji has been released. Wonder which Gfriend duet the fans will prefer? 1thek says, “This song is…