Refactor internal functions to InternalKeyguardTransitionInteractor

KeyguardTransitionInteractor exposes these internal functions that
should not be lightly used by any of its (many) callers. Also by virtue
of its size and scope the Single Responsibility Principle is not adhered
to.

Bug: 349785004
Flag: com.android.systemui.scene_container
Test: refactor_only
Change-Id: Ieeea795cbf75f1d68624142ef701a663a7f0c200