Notwithstanding anything contained in article 13, no law giving effect to the policy of the State towards securing 4 [all or any of the principles laid down in Part IV] shall be deemed to be void on the ground that it is inconsistent with, or takes away or abridges any of the rights conferred by article 14 or article 19 and no law containing a declaration that it is for giving effect to such policy shall be called in question in any court on the ground that it does not give effect to such policy:

Provided that where such law is made by the Legislature of a State, the provisions of this article shall not apply thereto unless such law, having been reserved for the consideration of the President, has received his assent.