Make static_assertions available to product and vendor

Bug: 270690570

Test: mma in external/rust/crates
Change-Id: I063a17f1c74057bb968ce586f75f37896a698103
diff --git a/Android.bp b/Android.bp
index af34fa5..05a9aa3 100644
--- a/Android.bp
+++ b/Android.bp
@@ -31,6 +31,7 @@
         "//apex_available:platform",
         "//apex_available:anyapex",
     ],
+    product_available: true,
     vendor_available: true,
     min_sdk_version: "29",
 }