Make libapexutil available to microdroid_launcher

microdroid_launcher uses this to create linker namespace links to the
APEXes.

Bug: 391225143
Test: apply aosp/3455572, run `vm_shell.sh start-microdroid
--auto-connect -- --debug full`. Check if the following line is shown.

01-21 04:36:29.358    70    70 I microdroid_launcher: Linked APEX
namespace com_android_i18n with shared libs
libicui18n.so:libicuuc.so:libicu_jni.so:libandroidicu.so:libicu.so

Change-Id: Ie87c25b9031883cdf347c7b357293aab38f39872
diff --git a/libs/libapexutil/Android.bp b/libs/libapexutil/Android.bp
index db0ec88..a37a5a7 100644
--- a/libs/libapexutil/Android.bp
+++ b/libs/libapexutil/Android.bp
@@ -40,7 +40,10 @@
         "//apex_available:platform",
         "com.android.runtime",
     ],
-    visibility: ["//system/linkerconfig"],
+    visibility: [
+        "//system/linkerconfig",
+        "//packages/modules/Virtualization/guest/microdroid_launcher",
+    ],
 }
 
 cc_test {