Make futures-core available to product and vendor

Bug: 270690570

Test: mma in external/rust/crates
Change-Id: Id741b2c6a24fe1dc38a5d3de9f54025a240c68f5
diff --git a/Android.bp b/Android.bp
index 08820ef..62feb3b 100644
--- a/Android.bp
+++ b/Android.bp
@@ -56,5 +56,7 @@
         "com.android.resolv",
         "com.android.virt",
     ],
+    product_available: true,
+    vendor_available: true,
     min_sdk_version: "29",
 }