Make native package manager available to platform.

Some native internal services are dependent on package manager which is
available only to specific APEXes. Also adding platform in general now.

Test: locally tested
Bug: 361877215
Change-Id: I01a015e83fbf07059936ffc2d50814d5827d609c

Author: vikram-gaur

libs/binder/Android.bp

@@ -829,6 +829,7 @@ aidl_interface {
     backend: {
         rust: {
             apex_available: [
+                "//apex_available:platform",
                 "com.android.virt",
             ],
             enabled: true,