Unify STManager behavior with no ST module

- Ensure all STManager methods throw IllegalState if they are called
when there is no STModule
- Retain getModuleProperties return null instead, as this behavior is
  used to determine if the STModule exists
- Minor cleanup to throw NPE if null is passed to several methods.
- AssertionError if fake HAL doesn't exist, since this should never
happen.

Bug: 272147641
Fixes: 279102299
Test: SoundTriggerManagerTest
Change-Id: Icf4a6a172b5bf706267586eb952960bae649b74c