INFORM6 rebind does not request lifetime option

[ColinMcInnes]

On a regular inform-request lifetime renewal, it requests option 32 Inform-Req refresh lifetime and applies the lifetime in the reply.

On a rebind, which triggers an inform-request, it does not request option 32, which results in it defaulting to IRT_DEFAULT if the server does not send it.

https://datatracker.ietf.org/doc/html/rfc8415#section-21.23

A DHCP client MUST request this option in the Option Request option
   (see [Section 21.7](https://datatracker.ietf.org/doc/html/rfc8415#section-21.7)) when sending Information-request messages.

Other options are requested normally. I will look into see if I can figure out what's different in the crafting of the inform-req message. All other options seem to be populated ok.