[audiopolicy][enginebase] Fix schema verification

Hidden stream type (e.g. rerouting/patch) and usages are not
part anymore of engine configuration schema.
This CL programmatically adds the internal system strategies
and volume associated.

Test: atest VtsHalAudioPolicyV1_0TargetTest
Bug: 141989952

Change-Id: I3d182bf374a4bd6ae10e7c408d51f83f6a2ea378
Signed-off-by: François Gaffie <francois.gaffie@renault.com>