[Physical Keyboard] Add intent support for PK layout setting page

This is part of feature for keyboard setting update, which allows gBoard to deep link to layout picker page.
document: go/deeplink_pk_layout_picker

Change-Id: I4277e175be7eed338f855e8144b5531c614e2c04
Bug: 318594345
Flag: com.android.settings.keyboard.keyboard_and_touchpad_a11y_new_page_enabled
Test: verified on Device

Android.bp

@@ -135,6 +135,7 @@ android_library {
         "android.app.flags-aconfig",
         "android.provider.flags-aconfig",
         "android.security.flags-aconfig",
+        "keyboard_flags",
     ],
 }