Fix that holding volume buttons to activate Extra dim feature doesn't do anything.

Root cause:
Original framework design which has 3 seconds restriction to prevent users from easily triggering the accessibility volume shortcut when first time using it.

Solution:
The system would bypass the 3 seconds restriction if users manually set any feature as the volume key shortcut.

Bug: 202602908
Test: make RunSettingsRoboTests ROBOTEST_FILTER=ToggleFeaturePreferenceFragmentTest
Change-Id: I324321577263904b6ff8b66e411766d16a6430dc

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

@@ -333,6 +333,10 @@ public abstract class AccessibilityShortcutPreferenceFragment extends DashboardF
         mShortcutPreference.setChecked(shortcutAssigned);
         mShortcutPreference.setSummary(getShortcutTypeSummary(getPrefContext()));
 
+        if (mHardwareTypeCheckBox.isChecked()) {
+            AccessibilityUtil.skipVolumeShortcutDialogTimeoutRestriction(getPrefContext());
+        }
+
         // Show the quick setting tooltip if the shortcut assigned in the first time
         if (shortcutAssigned) {
             showQuickSettingsTooltipIfNeeded();