Bluetooth: Mesh: Fix Friend node estalished

Since first poll request send by lpn use friend security
credentials, so, friend nodes should be able to decrypt with
friend security, even if they have not yet established a friendship.

Signed-off-by: Lingao Meng <menglingao@xiaomi.com>

Author: LingaoM

subsys/bluetooth/mesh/subnet.c

@@ -620,10 +620,6 @@ bool bt_mesh_net_cred_find(struct bt_mesh_net_rx *rx, struct net_buf_simple *in,
 	for (i = 0; i < ARRAY_SIZE(bt_mesh.frnd); i++) {
 		struct bt_mesh_friend *frnd = &bt_mesh.frnd[i];
 
-		if (!frnd->established) {
-			continue;
-		}
-
 		if (!frnd->subnet) {
 			continue;
 		}