[GDNative] fix godot_variant_evaluate function

Fixes #28984

(cherry picked from commit c1e733466bf8cd1dfe44787247c9ee54f4f85ae6)

modules/gdnative/gdnative/variant.cpp

@@ -518,7 +518,7 @@ void GDAPI godot_variant_evaluate(godot_variant_operator p_op, const godot_varia
 	const Variant *a = (const Variant *)p_a;
 	const Variant *b = (const Variant *)p_b;
 	Variant *ret = (Variant *)r_ret;
-	Variant::evaluate(op, a, b, *ret, *r_valid);
+	Variant::evaluate(op, *a, *b, *ret, *r_valid);
 }
 
 #ifdef __cplusplus