Remove mentions of "gesture" on the Accessibility Button settings page

Configures page to hide/replace elements that would mention gesture.
Also, provides context when necessary if a setting is disabled by the current button mode.

Demonstration video:
https://x20web.corp.google.com/users/jo/jonesriley/splitShortcut/a11yShortcutSettingsCleanup.mp4

Test: manual, navigate to the Accessibility Button "more options" page in gesture navigation mode. Verify there are no references to gesture.
Bug: 349178639
Flag: android.provider.a11y_standalone_gesture_enabled
Change-Id: I067738d23e74c00bab4010d187820d09013809ad

src/com/android/settings/accessibility/FloatingMenuFadePreferenceController.java

@@ -28,6 +28,7 @@ import androidx.preference.Preference;
 import androidx.preference.PreferenceScreen;
 import androidx.preference.TwoStatePreference;
 
+import com.android.settings.R;
 import com.android.settings.core.BasePreferenceController;
 import com.android.settingslib.core.lifecycle.LifecycleObserver;
 import com.android.settingslib.core.lifecycle.events.OnPause;
@@ -64,6 +65,18 @@ public class FloatingMenuFadePreferenceController extends BasePreferenceControll
                 ? AVAILABLE : DISABLED_DEPENDENT_SETTING;
     }
 
+    @Override
+    public CharSequence getSummary() {
+        if (mPreference != null) {
+            return mPreference.isEnabled()
+                    ? "%s"
+                    : mContext.getString(
+                            R.string.accessibility_button_disabled_button_mode_summary);
+        } else {
+            return "%s";
+        }
+    }
+
     @Override
     public void displayPreference(PreferenceScreen screen) {
         super.displayPreference(screen);
@@ -101,6 +114,7 @@ public class FloatingMenuFadePreferenceController extends BasePreferenceControll
 
     private void updateAvailabilityStatus() {
         mPreference.setEnabled(AccessibilityUtil.isFloatingMenuEnabled(mContext));
+        refreshSummary(mPreference);
     }
 
     private int getFloatingMenuFadeValue() {