Don't Show Work Profile Toast During Setup

Before device setup is complete, we shouldn't ever show the "using this
app outside your work profile" toast.  This toast is confusing in the
context of Setup Wizard.

Fixes: 150451876
Test: atest com.android.internal.app.IntentForwarderActivityTest
Test: Manually verified no toast during setup
Test: Manually verified toast appears after setup
Change-Id: I661cc18c625609726388f3705c7b893517e23323