[NS A44 1/2] Update linger state before processing listens

To compute accurately whether a network is in the background, the
linger state needs to be updated. Do that before computing whether
a network is in the background and possibly calling
applyBackgroundChangeForRematch.

However ! As of this patch, rematchNetworksAndRequests computes
a wrong value when adding to the list of affected networks, because
it is looking at intermediate global state. Somehow this used to
compensate exactly for the way reading back the state was wrong.
There might have been a few undetected bugs there, but none is
known.

As such, as of this patch, rematchNetworksAndRequests still
computes a wrong value while the computation when applying that
state now computes the right one, so the tests do not pass.
This patch must be checked in together with A44 2/2 which will
fix the computation in rematchNetworksAndRequests, but is kept
separate for ease of review.

Bug: 113554781
Test: ConnectivityServiceTest
Change-Id: Iaeed0d11bfa09f292f232ae020e944e430bc0184