TEST: replace deprecated cmocka macro in test_dyndns.c

Use will_return_ptr_always instead of will_return_always in the
will_return_nl_cache_foreach_always wrapper macro since the value
passed is a pointer, not an integer.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: claude

src/tests/cmocka/test_dyndns.c

@@ -243,7 +243,7 @@ void __wrap_nl_cache_foreach(struct nl_cache *cache,
     will_return(__wrap_nl_cache_foreach, data)
 
 #define will_return_nl_cache_foreach_always(data)      \
-    will_return_always(__wrap_nl_cache_foreach, data)
+    will_return_ptr_always(__wrap_nl_cache_foreach, data)
 
 #else /* HAVE_LIBNL */