New Jersey First Lady Tammy Murphy abruptly announced Sunday she is dropping her bid for U.S. Senate race, a stunning development that comes in the middle of a dramatic period for Garden State politics. Murphy, the wife of Gov. Phil Murphy, was running in the Democratic primary for the party’s nomination to take over for indicted fellow Democrat Robert Menendez and was quickly considered the favorite when she entered the race in November. But she has faced a fierce challenge from U.S. Rep. Andy Kim, who has harnessed support from progressive and grassroots groups and advocates in what has beco…