wifi-scripts: fix encryption setting of default OpenWrt SSID

wifi-scripts: fix encryption setting of default OpenWrt SSID

Commit 01a87f4bd0cdbfc84bbc172920e865c1600f7a45 changed the encryption
setting of the default SSID "OpenWrt" from "none" to "open". The correct
setting as per the documentation [1] is "none", though.
While this invalid setting won't cause a wrong hostapd setup, it will
at least cause malfunction in LuCI.

Change the default encryption setting back to "none".

[1] https://openwrt.org/docs/guide-user/network/wifi/basic#encryption_modes

Fixes: 01a87f4bd0cdbfc84bbc172920e865c1600f7a45
Signed-off-by: Shine <4c.fce2@proton.me>
Link: https://github.com/openwrt/openwrt/pull/21925
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>