Use acquireUnstableContentProviderClient instead of acquireContentProviderClient

Bug: 403512533
Test: TreeHugger
Test: manual
Test: atest SafetySourceBroadcastReceiverTest
Test: atest LockScreenSafetySourceTest
Test: atest ActiveUnlockStatusUtilsTest
Test: atest WearSafetySourceTest
Flag: com.android.settings.flags.biometrics_onboarding_education
Change-Id: I5b6683a4f65b85ba4902cc843d6f4e43f59651e0