Deleted dhcpv6_client_options_options_request_included_messages.go ma…

…nually.

Issue: CI failed ( https://github.com/open-traffic-generator/snappi/actions/runs/10504936061/job/29102168395 ) 
Existing class in model got deleted.
But previous CI run had resulted in this being checked into git.
So needed manual removal from git to match removal from model.