FirebaseUI for Android v4.2.1

FirebaseUI for Android v4.2.0 contains the following bug fixes:

• Fix scrollbar for country selector (#1192)
• Fix continue as guest icon vector paths (#1376)
• Fix ClassNotFoundException with FlowParameters (#1416 thanks @dimipaun)
• Fix anonymous auth button shadow in dark theme (#1476)
• Fix potential Facebook signin violation (#1465)
• Fix layout in landscape mode (#1434)
• Fix touch area being too small for some elements (#1415)

Notable transitive dependencies:

Dependency	Version
firebase-core	16.0.4
firebase-auth	16.0.5
play-services-auth	16.0.1
firebase-database	16.0.3
firebase-firestore	17.1.1
firebase-storage	16.0.3
Support Library	27.1.1