[wifi/ScoringParams] add nud param

nud=0 - request nud check after roaming, but not in response to score
nud=1 - check when score becomes very low
          ...
nud=10 - check when score first breaches threshold, and again as it gets worse

While here, add pps param unit tests and toString

Bug: 73383969
Test: updated unit tests
Change-Id: Ic468b456c1e17c80eaaa286fca0daea8baf0a9f1
2 files changed