grant CAP_WAKE_ALARM to AID_NETWORK_STACK

It is effectively an oversight that bluetooth has this
but network stack does not.

This prevents the network stack process from (for example)
using timerfd_create with CLOCK_{REAL,BOOT}TIME_ALARM,
without trampolining through parts of the mainline module
which are shipped as part of the system server.

See:
  https://man7.org/linux/man-pages/man2/timerfd_create.2.html

This change presumably depends on
https://android-review.googlesource.com/c/platform/system/sepolicy/+/2863215



Bug: 316171727
Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I3198262bc45cdd894fead211e9c3c6215dae71de