Make crossbeam-epoch available to product and vendor

Bug: 270690570

Test: mma in external/rust/crates
Change-Id: Ic744f8bb931f6d5a029c82e651256f9fab3094ba
diff --git a/Android.bp b/Android.bp
index 28c3aed..05f6061 100644
--- a/Android.bp
+++ b/Android.bp
@@ -90,4 +90,6 @@
         "//apex_available:platform",
         "//apex_available:anyapex",
     ],
+    product_available: true,
+    vendor_available: true,
 }