Fix NetworkScoreService#getActiveScorer.

Also fix its variant that returns package name for active scorer.

These were previously returning values from cached
NetworkScoreAppData that was created when ScoringServiceConnection was
created. Which means it does not correctly reflects the current state of
NetworkScoreAppData#mEnableUseOpenWifiActivity which could have been
disabled by USE_OPEN_WIFI_PACKAGE app to hide toggles.

I'm changing this to return dynamic values using NetworkScorerAppManager
methods.

Bug: 151160317
Bug: 150773571
Test: manual - verified that toggle is hidden if useOpenWifiActivity
component is disabled by USE_OPEN_WIFI_PACKAGE app.
Test: atest FrameworksNetTests
Test: atest NetworkScoreManagerTest

Change-Id: If76b1f03a1bf64a39063ac1fe0674be8b0131d3c