Increase SO_RCVBUF used in IpClientLinkObserver to 4MB and ignore ENOBUFS. am: 148f574281

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/modules/NetworkStack/+/18816727

Change-Id: Ic1e81656104acbe54a4cdc7176cfe21927ba5118
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>