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/accessibility/AccessibilitySettings.java

@@ -251,8 +251,8 @@ public class AccessibilitySettings extends DashboardFragment {
                     : context.getText(R.string.accessibility_summary_shortcut_disabled);
         } else {
             serviceState = serviceEnabled
-                    ? context.getText(R.string.accessibility_summary_state_enabled)
-                    : context.getText(R.string.accessibility_summary_state_disabled);
+                    ? context.getText(R.string.on)
+                    : context.getText(R.string.off);
         }
 
         final CharSequence serviceSummary = info.loadSummary(context.getPackageManager());