Use a configurable default if the setting has never been set.

AccessibilityManager#getAccessibilityShortcutTargets may not return
correct shortcut targets during boot. Needs to read settings directly.

Bug: 149293174
Bug: 147989561
Test: Manual test
Change-Id: Ia8997b08d11da78dab5cd568787e9c61b0b0eeab
1 file changed