Add default_visibility for soong modules

So that we don't get surprise usages.

Bug: 348717861
Test: m nothing
Change-Id: I47319a727092c1bd936cca88f5713ee977a48b48

cc/libbuildversion/Android.bp

@@ -20,4 +20,5 @@ cc_library_static {
         "//apex_available:anyapex",
     ],
     vendor_available: true,
+    visibility: ["//visibility:public"],
 }