Enable Assistant Media Session integration by default.

Bug: b/120559778
Test: Manual
Change-Id: I4498ec1160508afd6fccc9489a6e1fbe96bcc127
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2219352Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Commit-Queue: Li Lin <llin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#772926}

chromeos/services/assistant/public/cpp/features.cc

@@ -47,8 +47,7 @@ const base::Feature kEnableOnDeviceAssistant{"ChromeOSOnDeviceAssistant",
                                              base::FEATURE_DISABLED_BY_DEFAULT};
 
 const base::Feature kEnableMediaSessionIntegration{
-    "AssistantEnableMediaSessionIntegration",
-    base::FEATURE_DISABLED_BY_DEFAULT};
+    "AssistantEnableMediaSessionIntegration", base::FEATURE_ENABLED_BY_DEFAULT};
 
 // Disable voice match for test purpose.
 const base::Feature kDisableVoiceMatch{"DisableVoiceMatch",