By Natalie Grover and Ludwig Burger LONDON (Reuters) -Pfizer plans to sell its 32% stake in Haleon, its consumer health venture with British drugmaker GSK, after the business lists as an independent company in July, GSK said on Wednesday. GSK is spinning off Haleon, which makes Sensodyne toothpaste and Advil painkillers, so it can focus on vaccines and prescription drugs. GSK rejected a 50 billion pound ($63 billion) offer for Haleon last year, saying it undervalued the firm. Pfizer has previously indicated it wanted to sell its stake in Haleon but GSK, which owns 68% of the world’s biggest co…