As hard as it is to believe, Billy Idol, the English punk-turned-rock singer/songwriter who was a key part of the MTV-driven “Second British Invasion” in the ’80s — his hits include “Dancing with Myself,” “White Wedding,” “Cradle of Love,” “Eyes Without a Face” and a chart-topping cover of “Mony Mony” — is now 70 and a grandfather. But rest assured: his trademark sneer, spiky blonde hair and seductive voice are all still there. And his career, now in its 50th year, is still going strong. Indeed, since the darkest days of the pandemic, when “Dancing with Myself” experienced a resurgence in popularity (for obvious reasons), he has released two EPs (2021’s The Roadside and 2022’s The Cage) and a studio album (his first in 11 years, 2025’s Dream Into It); toured North America with old pal Joan Jett; and collaborated with ardent admirer Miley Cyrus on “Night Crawling,” a song on her 2020 album Plastic Hearts. He also was honored with a star on the Hollywood Walk of Fame in 2023 and nominated for induction into the Rock …