Allow index or data_view_id to be unknown (#1499)

* Allow index or data_view_id to be unknown

* CHANGELOG.md

Author: tobio

CHANGELOG.md

@@ -40,6 +40,7 @@ alias = [
 
 ### Changes
 
+- Allow `index` and `data_view_id` values to both be unknown during planning in `elasticstack_kibana_security_detection_rule` ([#1499](https://github.com/elastic/terraform-provider-elasticstack/pull/1499))
 - Support `.bedrock` and `.gen-ai` connectors ([#1467](https://github.com/elastic/terraform-provider-elasticstack/pull/1467))
 - Support the `solution` attribute in `elasticstack_kibana_space` from 8.16 ([#1486](https://github.com/elastic/terraform-provider-elasticstack/pull/1486)) 
 - Add `elasticstack_elasticsearch_alias` resource ([#1343](https://github.com/elastic/terraform-provider-elasticstack/pull/1343))

internal/kibana/security_detection_rule/schema.go

@@ -970,11 +970,10 @@ func (r securityDetectionRuleResource) ValidateConfig(ctx context.Context, req r
 
 	}
 
-	if !utils.IsKnown(data.Index) && !utils.IsKnown(data.DataViewId) {
+	if data.Index.IsNull() && data.DataViewId.IsNull() {
 		resp.Diagnostics.AddError(
 			"Invalid Configuration",
 			"One of 'index' or 'data_view_id' must be set.",
 		)
-
 	}
 }