Make proc-macro-nested available to product and vendor

Bug: 270690570

Test: mma in external/rust/crates
Change-Id: I19b4189522ac5c864bc56b1b582b029d7f397388
diff --git a/Android.bp b/Android.bp
index 22edf1a..2b68e36 100644
--- a/Android.bp
+++ b/Android.bp
@@ -63,5 +63,7 @@
         "com.android.resolv",
         "com.android.virt",
     ],
+    product_available: true,
+    vendor_available: true,
     min_sdk_version: "29",
 }