Make nix available to product and vendor

Bug: 270690570

Test: mma in external/rust/crates
Change-Id: I0476ba0779b89a9ba6bc9a17d6b61820d63c668b
diff --git a/Android.bp b/Android.bp
index 8241ba8..f471209 100644
--- a/Android.bp
+++ b/Android.bp
@@ -80,6 +80,7 @@
         "com.android.compos",
         "com.android.virt",
     ],
+    product_available: true,
     vendor_available: true,
     min_sdk_version: "29",
 }