audio: Fix SourceMetadata spec in HAL V7 VTS

Bug: 142480271
Test: atest VtsHalAudioV7_0TargetTest
Change-Id: Idb1130c9b0d32a41f22c49fa1d14ffe8ec2a3f3c
diff --git a/audio/core/all-versions/vts/functional/AudioPrimaryHidlHalTest.h b/audio/core/all-versions/vts/functional/AudioPrimaryHidlHalTest.h
index 2b9e336..61e99e8 100644
--- a/audio/core/all-versions/vts/functional/AudioPrimaryHidlHalTest.h
+++ b/audio/core/all-versions/vts/functional/AudioPrimaryHidlHalTest.h
@@ -928,9 +928,9 @@
     const SourceMetadata initMetadata = {
             { { toString(xsd::AudioUsage::AUDIO_USAGE_MEDIA),
                 toString(xsd::AudioContentType::AUDIO_CONTENT_TYPE_MUSIC),
-                {},
+                1 /* gain */,
                 toString(xsd::AudioChannelMask::AUDIO_CHANNEL_OUT_STEREO),
-                1 /* gain */ } }};
+                {} } }};
 #endif
 };
 TEST_P(OutputStreamTest, OpenOutputStreamTest) {