* Simplify StringJoiner to '+' since it only have one case
* Simplify Collections usage to use removeIf() and findFirst() directly
* Change class name SharedPreferenceUtils to PreferredShortcuts
Bug: 158540780
Test: atest ToggleFeaturePreferenceFragmentTest
Test: atest PreferredShortcutsTest
Change-Id: I02f03ccba09b6d7edaa5c0c8223ab3561a5e976b
* 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