Revert "internet: don't prove wildcards in referral answers"

This reverts commit 747869b5.

src/knot/nameserver/internet.c

@@ -514,9 +514,8 @@ static int solve_authority_dnssec(int state, knot_pkt_t *pkt, knotd_qdata_t *qda
 
 	/* RFC4035 3.1.3 Prove visited wildcards.
 	 * Wildcard expansion applies for Name Error, Wildcard Answer and
-	 * No Data proofs if at one point the search expanded a wildcard node.
-	 * \note Do not attempt to prove non-authoritative data. */
-	if (ret == KNOT_EOK && state != KNOTD_IN_STATE_DELEG) {
+	 * No Data proofs if at one point the search expanded a wildcard node. */
+	if (ret == KNOT_EOK) {
 		ret = nsec_prove_wildcards(pkt, qdata);
 	}