Fix fastly_service_waf_configuration not updating rule attributes correctly

[smaeda-ks]

from code comment:

// NOTE: Fastly WAF (WAF 2020) API doesn't have a proper batch update endpoint.
// go-fastly uses the below endpoint for UpsertBatchOperation:
// "POST /waf/firewalls/:firewall_id/versions/:version_id/active-rules"
// but this endpoint only updates "status" when it comes to upsert and "revision" field is ignored.
// Therefore, when one of the rule attributes is changed we must delete it first and create it as a new rule.

[Integralist]

LGTM.