AML: Make UserHandle.myUserId() available

Since the method UserHandle.myUserId() is a @SystemApi, build error
happens when building the mainline module.

This CL makes it available by building the APK with the system SDK.

Bug: 119749861
Test: mmm . (under frameworks/av/packages/MediaComponents)
Change-Id: Iedecf1a7c7de1279161601c1e88f959e89af73ac
diff --git a/packages/MediaComponents/apex/Android.bp b/packages/MediaComponents/apex/Android.bp
index 363a416..e797e14 100644
--- a/packages/MediaComponents/apex/Android.bp
+++ b/packages/MediaComponents/apex/Android.bp
@@ -20,7 +20,7 @@
 java_library {
     name: "media",
     installable: true,
-    sdk_version: "current",
+    sdk_version: "system_current",
     srcs: [
         "java/android/media/**/*.java",
         "java/android/service/**/*.java",
diff --git a/packages/MediaComponents/apex/java/android/media/session/MediaSession.java b/packages/MediaComponents/apex/java/android/media/session/MediaSession.java
index b3ebbc8..b40e3b0 100644
--- a/packages/MediaComponents/apex/java/android/media/session/MediaSession.java
+++ b/packages/MediaComponents/apex/java/android/media/session/MediaSession.java
@@ -150,9 +150,7 @@
      * @param tag A short name for debugging purposes.
      */
     public MediaSession(@NonNull Context context, @NonNull String tag) {
-        //TODO(b/119749861): Resolve hidden API usage, UserHandle.myUserId
-        //this(context, tag, UserHandle.myUserId());
-        this(context, tag, 0);  //TODO: remove this.
+        this(context, tag, UserHandle.myUserId());
     }
 
     /**