Keyguard translation - Emit value on start

Make sure that translationY emits a value on start. The combine flow
needs all flows to have started in order to work.

Fixes: 315495314
Test: atest KeyguardRootViewModelTest
Flag: ACONFIG com.android.systemui.keyguard_shade_migration_nssl
DEVELOPMENT

Change-Id: Icb9c42b5187718b1f776fb3f24a1ec1ed018344b
2 files changed