Fixed `permitjoin` being ignored in PUT request

[bram-mkse]

Fixed the value of permitjoin in the JSON body in a PUT request to /api/<apikey>/config being ignored. It was ignored due to startSearchLights() and startSearchSensors() overriding gwPermitJoinDuration to gwNetworkOpenDuration.

Now both functions take a duration to specify the duration of the permit join commmand.

[bram-mkse]

This fixes #6234.

I recreated this pull request because I polluted the commit history in the other one by accident. I didn't know that would happen. Learned something new today.

[Smanar]

Lol, I had so much suprises with github too ^^