Heat oven to 350° F. Coat an 8-cup fluted tube pan with cooking spray. Brew the tea in the water 3 to 5 minutes. Remove the tea bags or strain the leaves and set the brewed tea aside. Using a mixer, beat the butter, eggs, and granulated sugar until fluffy. Blend in the chocolate. Beat in the flour, baking soda, baking powder, salt, yogurt, and brewed tea. Pour into pan. Bake 50 minutes or until a skewer inserted into the cake comes out with a few crumbs attached. Remove from oven and let stand 5 minutes. Turn out of pan and cool. Dust with confectioners' sugar.