Anyone who tells you they know what’s next for Australian experimental-rock sextet King Gizzard & The Lizard Wizard is lying, with one exception: The hyper-prolific band is never not announcing a new album. This week, they unveiled The Silver Cord (Oct. 27, KGLW), previewing the synth-driven set with the lead single and video triumvirate of its album openers, “Theia / …