Remove duplicate strings.

"Yes" and "no" were redefined many times with no clear benefit, so this
consolidates them into one definition.

Bug: 243843096
Test: Build, install, and open the Settings app
Test: atest SettingsRoboTests
Change-Id: I5f84d09f223efd478461ded93aeac82bf7b128d8

src/com/android/settings/notification/zen/ZenModeSettings.java

@@ -194,7 +194,7 @@ public class ZenModeSettings extends ZenModeSettingsBase {
                 String description = ZenModeConfig.getDescription(mContext, true, config, false);
 
                 if (description == null) {
-                    return mContext.getString(R.string.zen_mode_sound_summary_on);
+                    return mContext.getString(R.string.on);
                 } else {
                     return mContext.getString(R.string.zen_mode_sound_summary_on_with_info,
                             description);