LOS ANGELES (Reuters) - Actress Lindsay Lohan's publicist fired back at the media on Thursday, saying journalists had crossed a line by mocking a heartfelt letter the screen star wrote following director Robert Altman's death last week. Spokeswoman Leslie Sloane said the note -- which one columnist suggested was composed by Lohan on "one of her legendary party benders" -- was instead dashed off by the distraught 20-year-old actress on a Blackberry, moments after she learned Altman had died. Altman, who died on November 20 at age 81, directed Lohan in the last film of his career, "A Prairie Home...