Physical keyboard related options shouldn't be searchable when invisible

Physical keyboard options category is hidden when there is no hardware
keyboard. It's related preferences are hidden in this case. Hence those
preferences shouldn't be searchable.

Bug: 351047456
Test: manually search "bounce keys", "sticky keys" and "slow keys",
they're not searchable when invisible on Accessibility page
Test: atest
Flag: com.android.settings.accessibility.fix_a11y_settings_search

Change-Id: I1eb465dd34e59d856bb1fa7c06bc253971a8c8d0

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

@@ -613,7 +613,7 @@ public class AccessibilitySettings extends DashboardFragment implements
         }
     }
 
-    private boolean isAnyHardKeyboardsExist() {
+    static boolean isAnyHardKeyboardsExist() {
         for (int deviceId : InputDevice.getDeviceIds()) {
             final InputDevice device = InputDevice.getDevice(deviceId);
             if (device != null && !device.isVirtual() && device.isFullKeyboard()) {