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/ToggleScreenMagnificationPreferenceFragment.java

@@ -361,6 +361,10 @@ public class ToggleScreenMagnificationPreferenceFragment extends
         mShortcutPreference.setChecked(value != UserShortcutType.EMPTY);
         mShortcutPreference.setSummary(
                 getShortcutTypeSummary(getPrefContext()));
+
+        if (mHardwareTypeCheckBox.isChecked()) {
+            AccessibilityUtil.skipVolumeShortcutDialogTimeoutRestriction(getPrefContext());
+        }
     }
 
     @Override