Add inline toggle for Prevent Ringing gesture.

- Fork sound_settings_v2 for dev.
- Replace Preference with PrimarySwitchPreference for the Prevent
Ringing entry.
- When the toggle is on, only show the status text without the on/off
info.
- Remove unused codes.

Bug: 174964721
Test: robotests
Change-Id: I990f5c778436c8058d4a5953c7f15a9a7eb580d8