PHOENIX — For six days, family members of 19-year-old April Guerra mourned her death because they thought she was killed in a car wreck.It turns out, she wasn’t.Arizona’s highest court said Friday the family cannot sue the state for negligence after officers mistakenly told them Guerra died in a 2010 rollover crash west of Phoenix.The officers confused Guerra’s identity with that of a close friend who was killed in the Interstate 10 wreck. That woman’s parents stood vigil at a hospital with a …