Prevent apps from supplying non-public ZenDeviceEffects

While allowing the system (and also the user, through probably they won't be toggles for these) to set them.

This also replaces fromSystemOrSystemUi by an enum-like in the public interface of ZenModeHelper, so dovetails with b/308671593 & co.

Fixes: 310938105
Test: atest ZenModeHelperTest
Change-Id: Ib8d2efca65748e67195f4b3a6a7f2f2532bea1da