LOS ANGELES — A Los Angeles City Hall proposal to send “john letters” to the owners of cars seen in areas known for prostitution has drawn criticism from a California civil liberties group.The City Council voted Wednesday to have the city attorney’s office analyze the proposal to use license numbers to determine who owns the vehicles.The letters would be written to discourage those who were soliciting prostitutes from returning to the area while posing no harm to those who were there for legitimate …