Reflect QS shortcut changes in a11y pages.

Bug: 314843909

Test: manual (modify qs tiles in QS panel while the a11y page is open,
verify the a11y page reflect the qs changes)
Test: atest com.android.settings.accessibility
Test: atest com.android.settings.accessibility.shortcuts

Flag: ACONFIG android.view.accessibility.a11y_qs_shortcut

Change-Id: Ie5b46459faab902912a214ca131eb5d0b105a7ef