This removes AccessibilityUtil.UserShortcutType,
replacing all mention of it with ShortcutConstants.UserShortcutType
NO_IFTTT=UI order not changed
Test: atest com.android.settings.accessibility
Bug: 322014084
Flag: EXEMPT internal refactoring
Change-Id: I18695d040c4bd08a455143594e770adda2b1a8de
* Add basic function equals(), hashcode() into data class
* Change flatternToString() to toString()
* Change constructor to fromString(flatternToString)
Bug: 158540780
Test: atest PreferredShortcutTest
Change-Id: I0ee46dd940d22ff9f168b95fe75d9cff2f0fddfb