[Biometric Onboarding & Edu] Update fingerprint settings page

- Added a feature provider for fingerprint settings page in
  FingerprintFeatureProvider for customization
- When no fingerprint enrolled, disabled the settings buttons instead of
  hiding them.
- Update new UX style for add fingerprint button

Bug: 370940762
Test: manual - 1. Enroll a fingerprint
               2. Go Fingerprint Settings page and remove fingerprint
	       3. Enroll fingerprint again
Test: atest FingerprintSettingsFragmentTest
Flag: com.android.settings.flags.biometrics_onboarding_education

Change-Id: Ibe47bb241c4b20e8e0c5b4a9172aef90bf3727ea