We have it on unimpeachable authority that Jane’s Addiction guitarist and occasional actor Dave Navarro — in the last few years he’s popped up on “Sons of Anarchy” and “Law & Order: Special Victims Unit” — splashed out $2.9 million for a brand-spanking new contemporary in L.A.’s historic Larchmont neighborhood. The nearly 4,300-square-foot residence, built by FMB development a on street lined mostly with far less modern bungalows, is arranged around a central courtyard with b