They say only the best parents get promoted to grandparents and 7 Little Johnstons stars Trent and Amber have clearly made the cut. The two TLC stars took to social media to share their birthday celebrations this year. The couple is starring in all-new episodes of their family’s show from March 12 alongside their kids Liz, Jonah, Alex, Emma, and Anna. In 7 Little Johnstons season 14, some exciting news comes to light when Elizabeth Johnston and Brice Bolden share they’re expecting their first child together. In November last year, they welcomed a daughter named Leighton Drew. Liz’s parents had…