Add null-check to audio effects usages

The tests are crashing on targets that return null to
AudioEffect.queryEffects().
Add null check to avoid this.

Test: atest AudioSecurityTest
Test: atest EffectBundleTest
Bug: 204513162
Change-Id: Ib72034aa005f8958e3adbe68f38db88d192500b9
(cherry picked from commit e4b45c76c559a88d70fad8bb1f72f7a9d614eb87)
2 files changed