Add the list of private DNS addresses to LinkProperties

(clean cherry-pick from ag/3874803)

Test: atest android.net.LinkPropertiesTest, also new tests pass
Bug: 73641539
Change-Id: If33a35b1354a67db09411ff098f20064797296ad
Merged-In: I4b739c56e658690532ae9deb0b9a3bc9b2adf8b0
Merged-In: I6bdbef78d078d68534c8e07e9af031ce374560ef
2 files changed