discoveryengine: add acl_enabled to google_discovery_engine_data_store

[JonathanvanWestendorp]

Adds the acl_enabled field to google_discovery_engine_data_store.

DataStore.aclEnabled is a create-time, immutable field of the Discovery Engine v1 API, but it is not currently exposed by the provider. Without it, users who need an ACL-enabled data store (so search enforces document-level permissions per end user) must create the data store out-of-band via the REST API / null_resource, outside Terraform state. This adds it as an immutable boolean.

document_processing_config (layout parsing + layout-based chunking) is already supported, so this single field is the remaining gap for provisioning an ACL-enabled, layout-parsed data store entirely in Terraform.

Closes hashicorp/terraform-provider-google#19566

Changes

• mmv1/products/discoveryengine/DataStore.yaml: new immutable acl_enabled property.
• New sample/test discoveryengine_datastore_acl_config (GENERIC vertical, CONTENT_REQUIRED, acl_enabled = true).

discoveryengine: added `acl_enabled` field to `google_discovery_engine_data_store` resource

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[github-actions]

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