[Settings] Make scribe setting default_on and secure

1. Migrate scribe pref to Settings.Secure
2. Consider enabled when not set.

Bug: 272376168
Test: atest StylusDevicesControllerTest StylusHandwritingPreferenceControllerTest.java


Change-Id: I4973a93c2cfe8c44f461b68fbda1a853e49340a2
4 files changed