Add Biometrics settings inside private space One Lock settings

This includes below changes:
- Add Biometrics preferernce in Private Space One Lock settings page
- Face and Fingerprint enrolment for Private profile
- Feature is behind flag android.multiuser.enable_biometrics_to_unlock_private_space

Screenshots:
go/ss/9cWZRAuvGGW7gMm.png
go/ss/B3NoFbL3KbpSzeN.png
go/ss/7xH3DLi9d6Lu2mR.png
go/ss/8WBEgKychWpduXg.png
go/ss/8pmPGshd9aiPvVC.png
go/ss/AFPBPbiaBBvTj3p.png
go/ss/3fE4XKLLUdP8LmF.png

Bug: 308862923
Test: atest CombinedBiometricStatusUtilsTest, atest FaceFingerprintUnlockControllerTest
Change-Id: I1853107a4df4fc97db53c97524c6d44a4f554e37

src/com/android/settings/Settings.java

@@ -57,7 +57,9 @@ public class Settings extends SettingsActivity {
     public static class CombinedBiometricProfileSettingsActivity extends SettingsActivity { /* empty */ }
     public static class TetherSettingsActivity extends SettingsActivity { /* empty */ }
     public static class WifiTetherSettingsActivity extends SettingsActivity { /* empty */ }
-
+    public static class PrivateSpaceBiometricSettingsActivity extends SettingsActivity {
+        /* empty */
+    }
     public static class VpnSettingsActivity extends SettingsActivity { /* empty */ }
     /** Activity for Data saver settings. */
     public static class DataSaverSummaryActivity extends SettingsActivity { /* empty */ }