feat(wifi): add ssid label to fortigate_wifi_client_info

[bastischubert]

see #415

[Semitour]

Hello, Thank you for the update.
Do you know when the next version will be released so we can implement this in our dashboards?

[lazyb0nes]

@Semitour Hi, I am working on a dashboard which will work for both HA clusters FGCP mainly and standalone nodes.
There are going to be some assumptions though that will be made clear in the dashboard docs, generally there are some things you just cannot get from the HTTP API, like sync status for example, so to get a complete view of the Fortigate you have to use SNMP for some smaller things.