UN Ambassador Mike Waltz's office is furious over a weekend Politico Magazine report that he's been quietly angling for Secretary of State Marco Rubio's job — and had the late Sen. Lindsey Graham's ear before Graham died in July.According to the report, Waltz sought the late South Carolina Republican's backing to replace Rubio, who many believe has "presidential ambitions of his own," if the job opens up. Two people say Graham told them separate…