DO NOT MERGE Allow iot_wifi domain to request the net_admin capability.

iot_wifi is an appdomain, like bluetooth, and currently requires the
net_admin capability so that it can use 'iw' to create a new virtual
Wifi interface. This should eventually be refactored into netd or
wificond so this can be reverted.

Bug: 64371898
Test: iot_wifi can get capability through NET_ADMIN permission.

Change-Id: I8a8a652bba5441af3aa07b8f65c014b7c3df3c42