Photo Credit: Carol RoseggAlan Alda and Candice Bergen replaced Carol Burnett and Brian Dennehy as the two life-long pen pals that rarely physically connect in A.R. Gurney's Love Letters at the Brooks Atkinson Theatre on November 9. This third Broadway rotation of famous pairs follows the play's usual bare-basics format, with no real set" just two chairs, a table, two scripts, two beverages and two actors that remain…