Filter out uninteresting UidObserver callbacks in NPMS

NPMS depends on three different process state thresholds for evaluating
network access. But holding the common lock for evaluating the network
rules may cause a lot of contention on the handler as uid changes are
frequent.
Separating out a fast check to filter out uninteresting proc-state
callbacks before posting to the handler for full evaluation of the
rules. This is especially useful when we use no cutpoint for the uid
observer registration.

This also fixes an inconsistency where changes crossing
TOP_THRESHOLD_STATE may not be received if the app transitioned
from some process-states below BFGS.

Test: atest FrameworksServicesTests:NetworkPolicyManagerServiceTest
Test: atest CtsHostsideNetworkTests

Bug: 319728914
Change-Id: Ia7a5aef1ce9705a55912749985c7ee950c24ac84