Don't let other networks fool the Switcher

It needs to be aware of all NetworkRequests regardless of whether
higher-scored NetworkFactories are satisfying them so we don't
switch off a phone just because we're on wifi.

Note that this behavior isn't necessarily bad, just a policy change,
unexpected and unwanted.

bug:27340021
Change-Id: I10a8d66c4117cbcb5db898c47f7cbdb1e2beb45b