Jennifer Garner paid it forward with a good deed at Starbucks. The ‘13 Going on 30’ star – who paid for the person behind her in line when she picked up a mint tea – emphasised the trick “ is always a worthwhile little act of kindness” urged others to follow in her footsteps on her Instagram Story. In a video she posted, the 49-year-old actress heard asking for a “mint mint tea grande” before handing over the money to pay for the person waiting next, adding: “If I give you this to pay for the people behind me, and then this for you guys. So, that’s for you guys. This is just to pay for whomeve…