feat: add dns_allow_external_traffic

[apeabody]

• Add new dns_allow_external_traffic bool to set control_plane_endpoints_config. dns_endpoint_config.allow_external_traffic

[bharathkkb]

LGTM
Regarding breaking change, I think this should be since private cluster users will now need to set dns_allow_external_traffic explicitly instead of the previous gating condition. Could another option be to temporarily allow both old gating condition (var.enable_private_endpoint && var.deploy_using_private_endpoint) or new var and then in the next major release we can clean up the old gating condition?

[apeabody]

LGTM Regarding breaking change, I think this should be since private cluster users will now need to set dns_allow_external_traffic explicitly instead of the previous gating condition. Could another option be to temporarily allow both old gating condition (var.enable_private_endpoint && var.deploy_using_private_endpoint) or new var and then in the next major release we can clean up the old gating condition?

That a great idea - I'll rework to gate on either condition (for private clusters) for now. Thanks!