[AudioServer][Strategies] Fix Min/Max index overwritting

When a strategy holds 2 stream types, following the same volume group
(aka same volume curves), when audioservice initializes, it may
overwritte the Min/max for the volume group.

This is due to the fact that the second stream type is not recognized
and falls back on default volume group (aka Music). So, Min/max are
overwritten with music Min/max.

This CL fixes the bug by formatting correctly the AudioAttributesGroups
of a product strategy by checking not only the volume group id but
also the stream type.

Bug: 136121584
Test: build & run cts-dev -m CtsMediaTestCase --test android.media.cts.AudioProductStrategyTest
run cts-dev -m CtsMediaTestCase --test android.media.cts.AudioVolumeGroupTest
run cts-dev -m CtsMediaTestCase --test android.media.cts.AudioVolumeGroupChangeHandlerTest
run cts-dev -m CtsMediaTestCase --test android.media.cts.AudioManagerTest#testPermissionsForVolumePerAttributes
run cts-dev -m CtsMediaTestCase --test android.media.cts.AudioManagerTest#testGetAndValidateProductStrategies
run cts-dev -m CtsMediaTestCase --test android.media.cts.AudioManagerTest#testGetAndValidateVolumeGroups
run cts-dev -m CtsMediaTestCase --test android.media.cts.AudioManagerTest#testSetGetVolumePerAttributesWithInvalidAttributes
run cts-dev -m CtsMediaTestCase --test android.media.cts.AudioManagerTest#testSetGetVolumePerAttributes
run cts-dev -m CtsMediaTestCase --test android.media.cts.AudioManagerTest#testVolumeGroupCallback

Change-Id: I3aab572ef4daeecce13bbcef6278edcc42b7d594
Signed-off-by: François Gaffie <francois.gaffie@renault.com>