netd.c: allow data saver egress from timewait sockets

This is a follow up to:
  https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2954728


as a result of taking a close look at all netd.c bpf_get_socket_uid() calls.

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I59b08a531a344bdab33a6c35aed210ef9356530c