wifi-scripts: ucode: create wpa_psk_file and sae_password_file when needed

wifi-scripts: ucode: create wpa_psk_file and sae_password_file when needed

This handles the case when 'wpad' or 'wpad-mini' package is used which is
missing WPA3 support. This makes it impossible to use ucode wifi-scripts
on such APs as it will raise an error:

   daemon.err hostapd: Line 87: unknown configuration item 'sae_password_file'

This also achieves parity with what is currently happening with old wifi-scripts.
The behavior now matches.

Fixes: https://github.com/openwrt/openwrt/issues/20781
Signed-off-by: Rany Hany <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/20784
Signed-off-by: Robert Marko <[email protected]>