Improvements to Settings Preference Service

- Remove explicit start/stop for client binding
- Add javadoc for clarifications
- Support Int type of Preference
- Use Intent instead of PendingIntent

Bug: 378674489
Bug: 375193223
Flag: com.android.settingslib.flags.settings_catalyst
Test: atest CtsSettingsPreferenceServiceTest
Change-Id: I6fe7916385ab16f204b2bacd80bf94444e25f7ef