Changes to the trigger segment

* Switch is always visible, even without a configuration activity
* Custom icon, title, and summary for some mode types (such as SCHEDULE_TIME, etc).
* Default texts in case of missing trigger description.
* Different icons for having/missing configuration activity.
* Move the section to the top of the screen.

Bug: 349376785
Test: atest ZenModeTriggerLinkPreferenceControllerTest
Flag: android.app.modes_ui
Change-Id: I960318899cf4da20ffc5765818429d5790d05067