Even before the waiter offers a menu, Selena Gomez lays her cards on the table. “I feel like I was supposed to go through everything I’ve gone through,” she says as she takes a seat at a rooftop restaurant in Los Angeles. “I had low self-esteem, and that’s something I work on continuously. But I feel so empowered because I’ve gained so much knowledge about what was going on mentally,” she adds. Soon after, she smiles mischievously and says, “Let’s talk about all the stuff I’m not supposed to.” She’s dressed like her 1990s style icon, Jennifer Aniston’s character Rachel Green, from Friends, wearing a shrunken ribbed...