audio effect: Avoid using stack-allocated arrays

This is to prevent OOB write in case when a sufficiently
large HIDL vector is provided via a HwBinder call.

Bug: 143787559
Test: atest VtsHalAudioEffectV5_0TargetTest
Change-Id: I6ea78804a5a3ed7a245929d3de47580b12c0da9a