[th/fix-wifi-mac-stable-ssid] device: fix generated 'wifi.cloned-mac-address="stable-ssid"' for stable-id
Setting
wifi.cloned-mac-address="stable-ssid"
should generate the same SSID as
connection.stable-id="${NETWORK_SSID}"
wifi.cloned-mac-address="stable"
For that to work correctly, we need to post-process the generated stable id.
Fixes: d210923c ('wifi: add "wifi.cloned-mac-address=stable-ssid"')