PHILADELPHIA — Critics of the proposed $1 billion settlement of NFL concussion claims want a full U.S. appeals court in Philadelphia to review a recent court decision that upheld the deal.The challengers believe the lead players’ lawyers negotiated away compensation for the key complaint in the original lawsuit, a brain disease known as chronic traumatic encephalopathy, because the science is still being developed.In their appeal Thursday, they said the lead players’ lawyers traded away the CTE issue in …